CN110073511B - Light-emitting element, light-emitting device, electronic equipment and lighting device - Google Patents

Abstract

A light-emitting element having high light-emitting efficiency and high reliability is provided. The light-emitting element includes a light-emitting layer containing a first organic compound and a guest material. The first organic compound has a substituted or unsubstituted carbazole skeleton. In the light-emitting layer, the weight ratio of a hydrocarbon group-substituted product in which at least one hydrogen atom in the first organic compound is substituted with a hydrocarbon group having 1 to 6 carbon atoms to the first organic compound is greater than 0 and 0.1 or less.

Description

Light-emitting element, light-emitting device, electronic equipment and lighting device

technical field

One embodiment of the present invention relates to a novel light-emitting element. Another embodiment of the present invention relates to a light-emitting element in which specified impurities are reduced. Another embodiment of the present invention relates to a light-emitting device, an electronic device, and a lighting device each including the light-emitting element.

Note that one embodiment of the present invention is not limited to the above technical field. One embodiment of the present invention relates to an object, method or method of manufacture. One embodiment of the present invention relates to a process, machine, product or composition. In particular, one embodiment of the present invention relates to a semiconductor device, a light-emitting device, a display device, a lighting device, a light-emitting element, or a method of manufacturing the same.

Background technique

The practical application of a light-emitting element (organic EL element) including an organic compound and utilizing electroluminescence (EL) is very active. In the basic structure of such a light-emitting element, an organic compound layer (EL layer) containing a light-emitting material is sandwiched between a pair of electrodes. By applying a voltage to the element to inject carriers, and utilizing the recombination energy of the carriers, luminescence can be obtained from the light-emitting material.

Since the above-mentioned light-emitting element is a self-luminous type light-emitting element, a display device using the light-emitting element has the following advantages: good visibility; no need for a backlight; low power consumption, and the like. Also, the light-emitting element has the advantages of being able to be made thin and light; and high response speed.

In the case of an organic EL element (OLED), a light-emitting element is produced using various organic compounds. Therefore, the quality of each organic compound is important because impurities in the organic compound may affect the characteristics of the light-emitting element. In particular, the reliability of elements is easily affected by impurities.

Therefore, in order to obtain a light-emitting element with good characteristics, especially a light-emitting element with high reliability, it is important to reduce impurities. Patent Document 1 and Patent Document 2 each disclose a light-emitting element in which reliability is improved by reducing the concentration of a halogen compound in an EL layer containing an organic compound to a certain level or less.

[references]

[Patent Literature]

[Patent Document 1] International Publication No. WO 00/41443

[Patent Document 2] Japanese Patent Application Laid-Open No. 2012-174901

SUMMARY OF THE INVENTION

It is known that some impurities deteriorate the characteristics of the light-emitting element, and some impurities do not affect the characteristics of the light-emitting element. Therefore, it is important to identify the type of impurities that deteriorate the characteristics of the light-emitting element. Furthermore, it is important to determine the impurity concentration that affects the light-emitting element. In addition, the mechanism for deteriorating the characteristics of the light-emitting element is hardly clear.

In view of the above, an object of one embodiment of the present invention is to provide a novel light-emitting element. In particular, the object is to provide a light-emitting element with high reliability. Another object of one embodiment of the present invention is to provide a light-emitting element with good luminous efficiency.

Another object of an embodiment of the present invention is to provide a light-emitting element with low power consumption. Another object of an embodiment of the present invention is to provide a novel lighting device. Another object of one embodiment of the present invention is to provide a light-emitting element, a light-emitting device, and an electronic apparatus each of which has high reliability. Another object of one embodiment of the present invention is to provide a light-emitting element, a light-emitting device, and an electronic device each of which has low power consumption.

In addition, the description of these purposes does not prevent the existence of other purposes. An embodiment of the present invention need not achieve all of the above objectives. In addition, objects other than these objects are evident from the description of the specification, drawings, claims, and the like, and objects other than these objects can be extracted from the description of the specification, drawings, claims, and the like.

One embodiment of the present invention is a light-emitting element including an EL layer between a pair of electrodes. The EL layer includes at least a light-emitting layer. The light-emitting layer contains the first organic compound and a hydrocarbon-based substituent. The first organic compound has a substituted or unsubstituted carbazole skeleton. The hydrocarbyl substituent has a structure in which at least one hydrogen atom of the first organic compound is substituted with a hydrocarbyl group having 1 to 6 carbon atoms. The weight ratio of the hydrocarbyl-substituted product to the first organic compound is more than 0 and 0.1 or less.

In the above structure, the hydrocarbyl substituent is preferably a compound in which at least one hydrogen atom of the first organic compound is substituted with a hydrocarbyl group having 1 to 6 carbon atoms. More preferably, the hydrocarbyl substituent is a compound in which at least one hydrogen atom of the carbazole skeleton of the first organic compound is substituted with a hydrocarbyl group having 1 to 6 carbon atoms. More preferably, the hydrocarbon group substituted product is a compound in which the hydrogen atom at the 2-position of the carbazole skeleton of the first organic compound is substituted with a hydrocarbon group having 1 to 6 carbon atoms.

In each of the above structures, the first organic compound preferably has a substituted or unsubstituted nitrogen-containing heteroaromatic ring.

In each of the above structures, the light-emitting layer may also include a second organic compound having a substituted or unsubstituted nitrogen-containing heteroaromatic ring.

In each of the above structures, the first organic compound is preferably an organic compound represented by the following general formula (G0).

[Chemical formula 1]

Note that in the general formula (G0), A represents a substituted or unsubstituted nitrogen-containing heteroaromatic ring having 1 to 25 carbon atoms, Ar represents an arylene group having 6 to 13 carbon atoms, and n represents 0 or 1 , Cz represents a substituted or unsubstituted carbazole skeleton.

In each of the above structures, the first organic compound is preferably an organic compound represented by the following general formula (G1).

[Chemical formula 2]

Note that, in the general formula (G1), A represents a substituted or unsubstituted nitrogen-containing heteroaromatic ring having 1 to 25 carbon atoms, Ar represents an arylene group having 6 to 13 carbon atoms, and n represents 0 or 1 , R ¹ to R ⁸ independently represent hydrogen, a hydrocarbon group with 1 to 6 carbon atoms, a cyclic hydrocarbon group with 3 to 6 carbon atoms, and a substituted or unsubstituted aromatic hydrocarbon group with 6 to 25 carbon atoms any of the .

In each of the above structures, the first organic compound is preferably an organic compound represented by the following general formula (G2).

[Chemical formula 3]

Note that in the general formula (G2), A represents a substituted or unsubstituted nitrogen-containing heteroaromatic ring having 1 to 25 carbon atoms, Ar represents an arylene group having 6 to 13 carbon atoms, and n represents 0 or 1 .

In each of the above structures, in the light-emitting layer, the weight ratio of the hydrocarbyl substituent to the first organic compound is preferably greater than 0 and 0.05 or less, and more preferably greater than 0 and 0.025 or less.

In each of the above structures, the guest material is preferably configured to convert triplet excitation energy into luminescence. Furthermore, the guest material preferably contains iridium.

One embodiment of the present invention is a display device including: a light-emitting element having any one of the above-described structures; and at least one of a color filter and a transistor. Another embodiment of the present invention is an electronic device including: the above-mentioned display device; and at least one of a frame body and a touch sensor. Another embodiment of the present invention is a lighting device including: a light-emitting element having any one of the above-described structures; and at least one of a frame body and a touch sensor. One embodiment of the present invention includes not only a light-emitting device having a light-emitting element but also an electronic apparatus having a light-emitting device within its scope. Therefore, the light-emitting device in this specification refers to an image display device or a light source (including a lighting device). The following display modules are also an embodiment of the present invention: a display module in which a flexible circuit board (FPC) or a tape carrier package (TCP) is connected to a light-emitting element; a display module in which a printed wiring board is provided on the TCP end; and an integrated circuit ( IC) is directly mounted to the display module of the light-emitting element by means of chip on glass (COG).

One embodiment of the present invention can provide a novel light-emitting element, especially a light-emitting element having high reliability. One embodiment of the present invention can provide a light-emitting element with high luminous efficiency. One embodiment of the present invention can provide a light-emitting element with low power consumption. One embodiment of the present invention can provide a novel light-emitting element. One embodiment of the present invention may provide a novel light emitting device. One embodiment of the present invention can provide a novel display device.

Note that the description of the above effects does not prevent the existence of other effects. It is not necessary for an embodiment of the present invention to achieve all of the above effects. Effects other than the above are clearly known and extracted from descriptions in the specification, drawings, claims, and the like.

Description of drawings

1A and 1B are schematic diagrams of a light-emitting element according to an embodiment of the present invention.

Figure 2 shows the spin density distribution of a material of one embodiment of the present invention.

Figure 3 shows the reaction of one embodiment of the present invention.

4A and 4B are schematic cross-sectional views showing a light-emitting element according to an embodiment of the present invention, and FIG. 4C is a graph showing a correlation of energy levels of a light-emitting layer.

5A and 5B are conceptual diagrams of an active matrix light-emitting device according to an embodiment of the present invention.

6A and 6B are conceptual diagrams each showing an active matrix light emitting device according to an embodiment of the present invention.

7 is a conceptual diagram showing an active matrix light-emitting device according to an embodiment of the present invention.

8A , 8B1 and 8B2 are schematic diagrams illustrating a display device according to an embodiment of the present invention.

9 is a circuit diagram of a display device according to an embodiment of the present invention.

10A and 10B are circuit diagrams of a display device according to an embodiment of the present invention.

FIG. 11 is a schematic diagram showing a display device according to an embodiment of the present invention.

FIG. 12 is a schematic diagram illustrating an electronic device according to an embodiment of the present invention.

13A and 13B are schematic diagrams illustrating a display device according to an embodiment of the present invention.

14A to 14G are diagrams illustrating an electronic device according to an embodiment of the present invention.

15A to 15C are diagrams each showing an electronic device according to an embodiment of the present invention.

16A to 16E are diagrams each showing an electronic device of one embodiment of the present invention.

17A to 17E are diagrams illustrating an electronic device according to an embodiment of the present invention.

18A to 18D are diagrams illustrating an electronic device of one embodiment of the present invention.

19A and 19B are diagrams illustrating an electronic device according to an embodiment of the present invention.

20A to 20C are diagrams illustrating a lighting device according to an embodiment of the present invention.

21A to 21D are diagrams each showing a lighting device according to an embodiment of the present invention.

22A to 22C are diagrams showing a lighting device according to an embodiment of the present invention.

FIG. 23 is a diagram illustrating a lighting device according to an embodiment of the present invention.

Figures 24A and 24B show the NMR spectra of the compounds of the Examples.

Figure 25 shows the MS spectrum of the example.

FIG. 26 shows absorption spectra and emission spectra of compounds of Examples.

FIG. 27 shows absorption and emission spectra of compounds of Examples.

FIG. 28 is a schematic diagram illustrating a light-emitting element of an embodiment.

FIG. 29 shows the current efficiency-luminance characteristics of the light-emitting element of the example.

FIG. 30 shows luminance-voltage characteristics of the light-emitting element of the example.

FIG. 31 shows the external quantum efficiency-brightness characteristics of the light-emitting element of the embodiment.

FIG. 32 shows the electroluminescence spectrum of the light-emitting element of the example.

FIG. 33 shows the result of the reliability test of the light-emitting element of the example.

Detailed ways

Hereinafter, embodiments and examples of the present invention will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the following description, and the modes and details of the present invention can be changed into various forms without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited only to the contents described in the embodiments and examples shown below.

For ease of understanding, the position, size, range, and the like of each structure shown in the drawings and the like may not represent the actual position, size, range, and the like. Therefore, the disclosed invention is not necessarily limited to the position, size, scope, etc. disclosed in the drawings and the like.

In addition, in this specification etc., ordinal numbers, such as "first" and "second", are added for the sake of convenience, and may not indicate the order of steps or the order of lamination. Therefore, for example, "first" can be appropriately replaced with "second" or "third" and the like can be described. In addition, the ordinal numbers described in the present specification and the like may not coincide with the ordinal numbers for specifying one embodiment of the present invention.

In this specification and the like, when the components of the present invention are described with reference to the drawings, the same reference numerals may be used in different drawings.

In this specification and the like, "film" and "layer" may be interchanged with each other. For example, a "conductive layer" may sometimes be referred to as a "conductive film". In addition, the "insulating film" may be referred to as an "insulating layer" in some cases.

In the present specification and the like, the singlet excited state (S ^* ) refers to a singlet state having excitation energy. The S1 energy level refers to the lowest energy level of the singlet excitation energy level, which refers to the excitation energy level of the lowest singlet excited state (S1 state). A triplet excited state (T ^* ) refers to a triplet state having excitation energy. In addition, the T1 level is the lowest energy level of the triplet excited energy level, and refers to the excitation energy level of the lowest triplet excited state (T1 state). In addition, in this specification and the like, even if it is simply expressed as "singlet excited state" and "singlet excited level", the S1 state and the S1 energy level may be expressed, respectively. In addition, even if it expresses as "triplet excited state" and "triplet excited energy level", it may represent a T1 state and a T1 energy level, respectively.

In the present specification and the like, a fluorescent compound refers to a substance that emits light in the visible light region when returning from a singlet excited state to a ground state. The phosphorescent compound refers to a substance that emits light in the visible light region at room temperature when returning from a triplet excited state to a ground state. In other words, the phosphorescent compound refers to a substance capable of converting triplet excitation energy into visible light.

In addition, in this specification etc., room temperature means the temperature of 0 degreeC or more and 40 degrees C or less.

In this specification and the like, the wavelength range of blue refers to a wavelength range of 400 nm or more and less than 500 nm, and blue light has at least one emission spectral peak in this range. The wavelength range of green refers to a wavelength range of 500 nm or more and less than 580 nm, and green light has at least one emission spectral peak in this range. The wavelength range of red refers to a wavelength range of 580 nm or more and 680 nm or less, and red light has at least one emission spectral peak in this range.

(Embodiment 1)

In this embodiment mode, a light-emitting element according to an embodiment of the present invention will be described with reference to FIGS. 1A , 1B, 2 and 3 .

<Structure example of light-emitting element>

First, the structure of a light-emitting element according to one embodiment of the present invention will be described with reference to FIGS. 1A and 1B .

FIG. 1A is a schematic cross-sectional view of a light-emitting element 150 according to an embodiment of the present invention.

The light-emitting element 150 includes a pair of electrodes (electrode 101 and electrode 102 ) and an EL layer 100 between the pair of electrodes. The EL layer 100 includes at least the light emitting layer 130 .

The EL layer 100 shown in FIG. 1A includes functional layers such as a hole injection layer 111 , a hole transport layer 112 , an electron transport layer 118 , and an electron injection layer 119 in addition to the light-emitting layer 130 .

In this embodiment mode, the electrode 101 of the pair of electrodes is used as the anode and the electrode 102 is used as the cathode. However, the structure of the light-emitting element 150 is not limited to this. That is, the electrode 101 may be used as a cathode and the electrode 102 may be used as an anode, and the layers between the electrodes may be stacked in reverse order. In other words, the hole injection layer 111 , the hole transport layer 112 , the light emitting layer 130 , the electron transport layer 118 , and the electron injection layer 119 may be stacked in this order from the anode side.

Note that the structure of the EL layer 100 is not limited to the structure shown in FIG. 1A , the EL layer 100 includes at least the light-emitting layer 130 and does not need to include the hole injection layer 111 , the hole transport layer 112 , the electron transport layer 118 and the electron injection layer 119 . Alternatively, the EL layer 100 may include a functional layer having the following functions: a function of reducing the injection barrier of holes or electrons; a function of improving the transportability of holes or electrons; a function of reducing the transportability of holes or electrons; The function of the quenching phenomenon caused by the electrode; or the function of inhibiting the diffusion of excitons. The functional layers can each be a single layer or a laminate.

FIG. 1B is a schematic cross-sectional view showing an example of the light emitting layer 130 shown in FIG. 1A . The light-emitting layer 130 shown in FIG. 1B includes a host material 131 and a guest material 132 .

The host material 131 contains at least the organic compound 131_1. The organic compound 131_1 is preferably a compound having an electron transport function (electron transport property), more preferably a compound having a nitrogen-containing heteroaromatic skeleton, and still more preferably a compound having a nitrogen-containing six-membered heteroaryl skeleton. A nitrogen-containing six-membered heteroaromatic skeleton is preferable because of its high electron transportability and stability.

Preferably, the host material 131 further contains an organic compound 131_2. The organic compound 131_2 is preferably a compound having a function of transporting holes (hole transport properties).

When the combination of the organic compound 131_1 and the organic compound 131_2 is a combination of a compound having electron transport properties and a compound having hole transport properties, the balance of carriers can be easily controlled according to the mixing ratio. Specifically, the weight ratio of the compound having electron transportability to the compound having hole transportability is preferably in the range of 1:9 to 9:1. By having this structure, the balance of carriers or the carrier recombination region (exciton generating region) can be easily controlled.

The guest material 132 may be a light-emitting organic compound, and the light-emitting organic compound is preferably a substance capable of emitting fluorescence (hereinafter, also referred to as a fluorescent compound) or a substance capable of emitting phosphorescence (hereinafter, also referred to as a phosphorescent compound). Hereinafter, a structure in which a fluorescent compound or a phosphorescent compound is used as the guest material 132 will be described.

The required characteristic of the light-emitting element 150 is high light-emitting efficiency. In addition, it is also required that the luminous efficiency decreases less during long-term storage or long-term driving, that is, long service life or high reliability. In order to make the light-emitting element 150 have high light-emitting efficiency and high reliability, the EL layer 100, especially the light-emitting layer 130 preferably includes an organic compound with a low impurity content. Examples of impurities include those in which hydrogen atoms of organic materials are substituted with hydrocarbon groups or halogens. It is particularly preferable that the halide content of the organic compound included in the EL layer 100 is low.

In order to manufacture a light-emitting element with a low impurity content, it is preferable to use a high-purity organic compound for the light-emitting element. Therefore, it is preferable to synthesize the organic compound using a reagent with few impurities or a solvent with high purity. This is because impurities contained in the reagents used in the synthesis may be included in the intended organic compound. As purification of the organic compound, sublimation purification is generally performed. By sublimation purification, impurities such as solvent remaining after synthesis and trace amounts of halides can be removed.

However, for example, in the purification process of the organic compound, it is difficult to remove some impurities due to the similar molecular structure to that of the organic compound included in the EL layer 100 . Therefore, organic compounds sometimes contain such impurities whose content is difficult to reduce. Impurities are sometimes mixed in the light-emitting element, and the light-emitting element is made to contain impurities. For example, a substance generated by decomposition of an organic compound during vacuum deposition may be mixed into a light-emitting element as an impurity. In addition, for example, when a production method using a solvent such as a coating method, an inkjet method, or a printing method is employed, the solvent or impurities in the solvent may be mixed into the light-emitting element. In addition, there is a possibility that substances generated by decomposition of the organic compound during driving of the light-emitting element may be mixed into the light-emitting element as an impurity. Therefore, it is difficult to remove all impurities in the light-emitting element.

As described above, it is difficult to form the EL layer 100 without including impurities, but the inventors of the present invention found that the impurities whose concentration is below a certain level do not affect the characteristics of the light-emitting element. Specifically, in the light-emitting element according to one embodiment of the present invention, the light-emitting layer 130 contains a guest material and an organic compound having a carbazole skeleton as host materials. In the light-emitting element, the weight ratio of the hydrocarbon-based substituent to the host material is greater than 0 and 0.1 or less, and the hydrocarbon-based substituent is used as an impurity and has at least one hydrogen atom of the host material contained in the light-emitting layer 130 replaced by a carbon atom. Hydrocarbyl-substituted structures with numbers from 1 to 6.

Note that when the hydrocarbyl substitution is a methyl substitution, the methyl substitution has m/z represented by m/z+14n (n is a natural number) of the host material.

The weight ratio of the hydrocarbyl substituent with respect to the host material is preferably more than 0 and 0.05 or less, and more preferably more than 0 and 0.025 or less.

An organic compound having a carbazole skeleton is suitable for use in a light-emitting element because of its high T1 level and high carrier transport.

Carbazole derivatives sometimes used as raw materials for organic compounds having a carbazole skeleton for light-emitting elements include hydrocarbon groups in which the hydrogen atoms of the carbazole skeleton are replaced by hydrocarbon groups having 1 to 6 carbon atoms (in many cases, the number of carbon atoms is 1 to 4 alkyl, especially methyl) substituted hydrocarbyl substituents as impurities. This is because the physical properties of the hydrocarbyl substituent are similar to those of the target substance (an organic compound having a carbazole skeleton or a carbazole derivative used as a raw material of an organic compound), and thus it is difficult to purify and remove the hydrocarbyl substitution.

As described above, the organic compound having a carbazole skeleton sometimes includes a hydrocarbon substituent as an impurity, which may adversely affect the characteristics of the light-emitting element.

<Analysis of the influence of impurities by quantum chemical calculation>

Here, an analysis of the influence of a hydrocarbyl substitution of an organic compound having a carbazole skeleton on a light-emitting element will be described using quantum chemical calculation.

Hereinafter, organic compounds each having a carbazole skeleton used for analysis and their names are shown.

[Chemical formula 4]

In the light-emitting element, 35DCzPPy is used as the material of the electron transport layer or the light-emitting layer. Me-35DCzPPy is a substance considered as an impurity contained in 35DCzPPy, and can be said to be a methyl substitution of 35DCzPPy.

For each triplet excited state (T1) of 35DCzPPy and Me-35DCzPPy, oscillation (spin density) analysis of each of the most stable structure with the lowest T1 energy level and the metastable structure was performed. Calculations were performed using the density functional method (DFT). Figure 2 shows the results. In DFT, the total energy is expressed as the sum of potential energy, electrostatic energy between electrons, kinetic energy of electrons, and exchange correlation energy including all complex interactions between electrons. In addition, in DFT, since the exchange-correlation action is approximated using a functional function of one electron potential expressed by electron density (a function of other functions), high-speed calculation can be performed. Here, the weight of each parameter related to the exchange correlation energy is defined using B3LYP, which is a hybrid functional. 6-311G(d,p) was used as the basis function. Gaussian 09 was used as the calculation program.

In Figure 2, the shaded part of the molecule shows the position of the spin present in the T1 excited state. There is no significant difference in the spin density distribution of the most stable structure of T1 of 35DCzPPy and Me-35DCzPPy, and it can be seen that the spin easily extends to the pyridine ring and the phenylene. On the other hand, it was found that the spin of the metastable structure of T1 in each of 35DCzPPy and Me-35DCzPPy extends mainly to the carbazole ring, and in Me-35DCzPPy, the spin extends to the methyl group. Note that the spin density of the methyl group is about 3% of the entire substance. Note that the ratio of spin densities is calculated from the sum of the absolute values of the spin densities of the respective atoms.

Note that the calculation steps are as follows: the most stable structure of the ground state (S0 state) is regarded as the initial structure, and the metastable structure of T1 is obtained by recalculation of the most stable structure of T1. The most stable structure of T1 is obtained by setting the initial structure so that electrons of the spin of the T1 excited state are easily present in the pyridine ring and the phenylene group. The excitation energies are each the difference between the energy of the most stable structure of the SO state and the energy of each of the most stable structure of T1 and the metastable structure of T1 . Note that when recalculation of the most stable structure of the S0 state is performed with the most stable structure of T1 as the initial structure, the structure and energy values are the same as those of the most stable structure of the S0 state calculated above.

In other words, it can be said that considering the structural change of Me-35DCzPPy from the ground state (S0 state) to the T1 excited state caused by the excitation, compared with the structural change between the ground state and the metastable structure of T1, the most Structural changes between stable structures occur less frequently because the molecular twist in the structural changes between the ground state of the molecule and the most stable structure of T1 is greater than the molecular twist in the structural changes between the ground state and the metastable structure of T1. In addition, it can be said that compared with 35DCzPPy in the excited state of T1, Me-35DCzPPy in the excited state of T1 is more likely to have the metastable structure of T1, because the energy difference between the most stable structure of T1 and the metastable structure of T1 is small, which is 0.09eV. As described above, the spin in Me-35DCzPPy having the metastable structure of T1 extends to the methyl group, so that a reaction starting from the methyl group sometimes occurs.

Next, using quantum chemical calculations, the hydrogen atom migration reaction was analyzed. In this reaction, due to the interaction between the methyl group and the pyridine ring in the two molecules of Me-35DCzPPy, the hydrogen atom of the methyl group migrated to the pyridine ring, CH2-35DCzPPy and Me-35DCzPPy _- H were generated. Below, the reaction formula used for the analysis and the name of the organic compound used for the analysis are shown.

[Chemical formula 5]

FIG. 3 shows a reaction path and energy diagram obtained by analyzing the hydrogen atom transfer reaction in the lowest triplet excited state.

In FIG. 3 , Me-35DCzPPy in the T1 state and Me-35DCzPPy in the ground state (S0 state) are based on the energy infinitely far away from the solution state. The activation energy of the reaction in which the hydrogen atom of the methyl group is transferred to the pyridine ring is 0.54 eV, and the reaction can occur at room temperature. In addition, in the final state after the hydrogen atoms migrate, both CH ₂ -35DCzPPy and Me-35DCzPPy-H are in the free radical state, and the energy of the final state is lower and stable than that of the initial state, and the reaction is an exothermic reaction. From this, it can be seen that in the light-emitting layer (excited state) in the state of driving the light-emitting element, hydrogen is likely to be generated in the state of the molecular arrangement in which the interaction between the methyl group and the pyridine ring of the two molecules of Me-35DCzPPy is generated. Atom migration reaction.

When the light-emitting element is driven, the generated CH ₂ -35DCzPPy in a radical state and Me-35DCzPPy-H in a radical state receive electrons or holes and are in a singlet ground state. Table 1 shows the calculated values of the T1 energy level of CH ₂ -35DCzPPy in an anion state by accepting electrons and the T1 energy level of Me-35DCzPPy-H in a cation state by accepting holes. Also shown is the measured value of the T1 level of Me-35DCzPPy.

Note that the calculation was performed by the same method as the calculation of the T1 level of Me-35DCzPPy.

[Table 1]

the name of the substance T1 energy level (eV) Me-35DCzPPy 2.75 (measured value) CH₂-35DCzPPy in anionic state 0.50 (calculated value) Me-35DCzPPy-H in the cationic state 1.41 (calculated value)

As shown in Table 1, the T1 energy level of CH ₂ -35DCzPPy in the anion state and the T1 energy level of Me-35DCzPPy-H in the cation state due to the hydrogen atom transfer reaction are very low. Therefore, this may lead to deactivation in the light-emitting element. In other words, excitation energy is transferred from the excited state guest material or host material to CH ₂ -35DCzPPy in the anionic state and Me-35DCzPPy-H in the cationic state. Therefore, light emission from the guest material cannot be obtained, and the light emission efficiency of the light emitting element decreases.

As described above, when a light-emitting element including a compound in which a hydrogen atom of a carbazole skeleton is substituted with a methyl group is driven, a substance that may cause deactivation may be generated in the light-emitting element, which may adversely affect reliability. Therefore, the content of the compound in which the hydrogen atom of the carbazole skeleton is substituted with a methyl group is preferably low. As described above, the spin density of the methyl group of Me-35DCzPPy in the T1 state is about 3% of the entire substance, and it is predicted that when the content of the substance that may cause deactivation is approximately the same as that of the guest material, the substance will adversely affect the light-emitting element. influences. Therefore, the weight ratio of the substance that may cause inactivation to the host material is preferably more than 0 and 0.1 or less, more preferably more than 0 and 0.05 or less, and still more preferably more than 0 and 0.025 or less.

Note that the calculation is performed in the case where the substituent of the carbazole skeleton is a methyl group, however, the above reaction is not limited to a methyl group. When the substituent is a hydrocarbon group, at least an aliphatic hydrocarbon group, the same reaction as described above occurs.

Note that the calculation is made for the reaction with the nitrogen of the pyridine skeleton, but the above reaction is not limited to the pyridine skeleton. The same reaction described above is predicted to occur in the case of nitrogen-containing heteroaromatic compounds. At least in the case of a compound having a nitrogen-containing six-membered heteroaromatic ring, the same reaction as described above occurs. That is, in the case of a compound having a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring or a triazine ring, the same reaction as described above occurs. In other words, this is a phenomenon that occurs in the case of heteroaromatic compounds with non-shared electron pairs.

The above-mentioned reaction occurs when the hydrocarbyl-substituted substance has a structure in which at least hydrogen atoms of the host material of the light-emitting layer are substituted with hydrocarbyl groups.

Therefore, one embodiment of the present invention is a light-emitting element including a light-emitting layer containing a first organic compound having a substituted or unsubstituted carbazole skeleton. The first organic compound is a compound having a nitrogen-containing six-membered heteroaromatic ring or a heteroaromatic compound having a non-shared electron pair. Alternatively, the light-emitting element includes a light-emitting layer containing not only the first organic compound but also the second organic compound. The second organic compound is a compound having a nitrogen-containing six-membered heteroaromatic ring or a heteroaromatic compound having a non-shared electron pair.

Note that in this calculation, the case where the radical molecule generated in this calculation accepts electrons or holes and is in a singlet ground state is analyzed, but the radical generated in a light-emitting element generally has high reactivity, so it is not compatible with other organic materials (host materials). and guest materials, etc.) react, sometimes resulting in deterioration. The free radical itself has low excitation energy and may easily become a quenching factor.

Note that in the above calculations, quantum chemical calculations were performed for the hydrogen atom migration reaction between two molecules of Me-35DCzPPy, however, it was assumed that Me-35DCzPPy in the excited state, that is, the T1 state or the S1 state, and the ground state (S0 state) The same reaction as above occurs between the 35DCzPPy of , and the quantum chemical calculation is carried out, and the same result as the above calculation result can be obtained at this time. This is because the above reaction is a reaction between the methyl group bonded to the carbazole skeleton and the nitrogen of the pyridine skeleton.

The above-mentioned hydrogen atom migration reaction occurs between two molecules of different substances. When an organic compound in which at least one hydrogen atom of the carbazole skeleton is substituted with a hydrocarbon group having 1 to 6 carbon atoms and an organic compound having a nitrogen-containing heteroaromatic ring coexist in the light-emitting layer, a hydrogen atom migration reaction may occur.

As the above calculation, a quantum chemical calculation involving a reaction keyed to the methyl group of the carbazole skeleton was performed, but the above reaction is not limited to the substituent of the carbazole skeleton. In the case where the substituent as the spin-extended skeleton includes a hydrocarbon group, the same reaction as described above is predicted to occur.

In the above, the quantum chemical calculation was performed for the hydrogen atom migration reaction, but as described above, the spin is extended to the methyl group of Me-35DCzPPy in the T1 state. Therefore, other than the hydrogen atom transfer reaction, a reaction starting from a methyl group may also occur. At this time, as in the hydrogen atom migration reaction, Me-35DCzPPy is converted into a radical molecule, which may be a quenching factor, resulting in deterioration of the light-emitting element. Therefore, the content of the compound in which the hydrogen atom of the carbazole skeleton is substituted with a methyl group is preferably low, and the weight ratio of the compound in which the hydrogen atom of the carbazole skeleton is substituted with a methyl group relative to the host material is greater than 0 and 0.1 or less, more preferably greater than 0 and 0.05 or less, more preferably more than 0 and 0.025 or less.

<Material>

Next, the constituent elements of the light-emitting element according to one embodiment of the present invention will be described in detail.

"Luminous Layer"

The light-emitting layer 130 includes at least a host material 131 , and preferably further includes a guest material 132 . The host material 131 may contain an organic compound 131_1 and an organic compound 131_2. In the light-emitting layer 130 , the host material 131 exists in the largest weight ratio, and the guest material 132 is dispersed in the host material 131 . When the guest material 132 is a fluorescent compound, the S1 energy level of the host material 131 (organic compound 131_1 and organic compound 131_2 ) of the light emitting layer 130 is preferably higher than the S1 energy level of the guest material (guest material 132 ) of the light emitting layer 130 . When the guest material 132 is a phosphorescent compound, the T1 energy level of the host material 131 (organic compound 131_1 and organic compound 131_2 ) of the light emitting layer 130 is preferably higher than the T1 energy level of the guest material (guest material 132 ) of the light emitting layer 130 .

The host material 131 is preferably a compound having a carbazole skeleton. Specific examples of carbazole derivatives include: 3-[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzDPA1), 3,6-bis[ N-(4-Diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzDPA2), 3,6-bis[N-(4-diphenylaminophenyl) -N-(1-naphthyl)amino]-9-phenylcarbazole (abbreviation: PCzTPN2), 3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9 -Phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2) , 3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1), N,N-diphenyl- 9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: CzA1PA), 4-(10-phenyl-9-anthryl)triphenylamine ( Abbreviation: DPhPA), 4-(9H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl) triphenylamine (abbreviation: YGAPA), N,9-diphenyl-N- [4-(10-Phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), N,9-diphenyl-N-{4-[4-(10 -Phenyl-9-anthryl)phenyl]phenyl}-9H-carbazol-3-amine (abbreviation: PCAPBA), N,9-diphenyl-N-(9,10-diphenyl-2 -Anthracenyl)-9H-carbazol-3-amine (abbreviation: 2PCAPA), 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: 2PCAPA) : PCzPA), 3,6-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: DPCzPA).

When the host material 131 includes the organic compound 131_1 and the organic compound 131_2, the organic compound 131_1 has a carbazole skeleton, and preferably further has a nitrogen-containing six-membered heteroaryl skeleton. Specific examples of the nitrogen-containing six-membered heteroaryl skeleton include compounds having any of a pyridine skeleton, a diazine skeleton (pyrazine skeleton, a pyrimidine skeleton, and a pyridazine skeleton), and a triazine skeleton. Examples of these basic compounds having a nitrogen-containing heteroaromatic skeleton include pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, triazine derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, phenanthrene derivatives Roroline derivatives, purine derivatives and other compounds. As the organic compound 131_1, a material (electron-transporting material) having higher electron-transporting properties than hole-transporting properties can be used, and preferably a material having an electron mobility of 1×10 ^-6 cm ² /Vs or more is used. Note that these materials can also be applied to the host material 131 , that is, the host material of the light-emitting layer contains one or more kinds of materials.

Specifically, for example, 2-[3-(3,9'-bi-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzCzPDBq), 4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm) and other heterocyclic compounds having a diazine skeleton, 2-{4-[3-(N- Triazine such as phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn) Heterocyclic compounds having a skeleton, and heterocyclic compounds having a pyridine skeleton such as 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy). Among the above heterocyclic compounds, a heterocyclic compound having a triazine skeleton, a diazine (pyrimidine, pyrazine, pyridazine) skeleton or a pyridine skeleton is preferably used because of high reliability and stability. In addition, the heterocyclic compound having this skeleton has high electron transport properties, which also contributes to lowering the driving voltage.

As the organic compound 131_1, the following heteroaromatic compounds can be used in addition to the above-mentioned heteroaromatic compounds.

Heterocyclic compounds having a pyridine skeleton, such as phenanthroline (abbreviation: BPhen) and bathcoperol (abbreviation: BCP), and 2-[3-(dibenzothiophen-4-yl)phenyl]diphenyl [f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline phenoline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2 -[4-(3,6-Diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-( Dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II), 6-[3-(dibenzothiophen-4-yl)phenyl]di Benzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), 4,6-bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis [3-(4-Dibenzothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 1,3,5-tris[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB ) and other heterocyclic compounds having a diazine skeleton. In addition, poly(2,5-pyridinediyl) (abbreviation: PPy), poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl) can also be used base)] (abbreviation: PF-Py), poly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2'-bipyridine-6,6'-diyl) ] (abbreviation: PF-BPy) and other polymer compounds. The substances listed here are mainly substances having an electron mobility of 1×10 ^-6 cm ² /Vs or more. However, any substance other than the above-mentioned substances may be used as long as the substance has higher electron transport properties than hole transport properties.

The organic compound 131_2 may be a compound having a nitrogen-containing five-membered heterocyclic skeleton or a tertiary amine skeleton, and preferably has a nitrogen-containing five-membered heterocyclic skeleton. Specifically, a pyrrole skeleton or an aromatic amine skeleton can be mentioned. Specifically, an indole derivative, a carbazole derivative, a triarylamine derivative, etc. are mentioned. Examples of the nitrogen-containing five-membered heterocyclic skeleton include an imidazole skeleton, a triazole skeleton, and a tetrazole skeleton. As the organic compound 131_2, a material (hole-transporting material) having a higher hole-transporting property than electron-transporting property can be used, and a material having a hole mobility of 1×10 ^-6 cm ² /Vs or more is preferable. In addition, the above-mentioned hole-transporting material may be a polymer compound. Among the above-mentioned compounds having a carbazole skeleton, compounds having a hole mobility of 1×10 ^-6 cm ² /Vs or more can be appropriately used.

Examples of aromatic amine compounds that can be used as materials with high hole transport properties include N,N'-bis(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviation: DTDPPA), 4 , 4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), N,N'-bis{4-[bis(3-methylphenyl) Amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviation: DNTPD), 1,3,5-tri[N-(4 -Diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), etc.

Other examples are poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N-(4-{N'-[4-(4- Diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide] (abbreviation: PTPDMA), poly[N,N'-bis(4-butylphenyl)-N , N'-bis (phenyl) benzidine] (abbreviation: Poly-TPD) and other polymer compounds.

Examples of materials with high hole transport properties are: 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB or α-NPD), N,N'-bis (3-Methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviation: TPD), 4,4',4"-triphenyl (Carbazol-9-yl)triphenylamine (abbreviation: TCTA), 4,4',4"-tris[N-(1-naphthyl)-N-phenylamino]triphenylamine (abbreviation: 1'-TNATA) , 4,4',4"-tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4',4"-tris[N-(3-methylphenyl)-N- Phenylamino]triphenylamine (abbreviation: MTDATA), 4,4'-bis[N-(spiro-9,9'-bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB), 4 -Phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), N-(9,9-dimethyl-9H-fluoren-2-yl)-N-{9,9-dimethyl-2-[N'-phenyl-N'-(9,9 -Dimethyl-9H-fluoren-2-yl)amino]-9H-fluoren-7-yl}phenylamine (abbreviation: DFLADFL), N-(9,9-dimethyl-2-diphenylamino- 9H-Fluoren-7-yl)diphenylamine (abbreviation: DPNF), 2-[N-(4-diphenylaminophenyl)-N-phenylamino]spiro-9,9'-bifluorene (abbreviation: DPASF), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl) triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4"-(9-benzene Base-9H-carbazol-3-yl) triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl) triphenylamine (abbreviation: PCBBi1BP) : PCBANB), 4,4'-bis(1-naphthyl)-4"-(9-phenyl-9H-carbazol-3-yl) triphenylamine (abbreviation: PCBNBB), 4-phenyldiphenyl -(9-Phenyl-9H-carbazol-3-yl)amine (abbreviation: PCA1BP), N,N'-bis(9-phenylcarbazol-3-yl)-N,N'-diphenyl Benzene-1,3-diamine (abbreviation: PCA2B), N,N',N"-triphenyl-N,N',N"-tris(9-phenylcarbazol-3-yl)benzene-1 , 3,5-triamine (abbreviation: PCA3B), N-(4-biphenyl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9-phenyl-9H-carbohydrate Azol-3-amine (abbreviation: PCBiF), N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl] -9,9-dimethyl-9H-fluorene-2-amine (abbreviation: PCBBiF), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbohydrate) Azol-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]spiro- 9,9'-bifluorene-2-amine (abbreviation: PCBASF), 2-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]spiro-9,9'-bifluorene ( Abbreviation: PCASF), 2,7-bis[N-(4-diphenylaminophenyl)-N-phenylamino]-spiro-9,9'-bifluorene (abbreviation: DPA2SF), N-[4-( 9H-carbazol-9-yl)phenyl]-N-(4-phenyl)phenylaniline (abbreviation: YGA1BP), N,N'-bis[4-(carbazol-9-yl)phenyl] -N,N'-diphenyl-9,9-dimethylfluorene-2,7-diamine (abbreviation: YGA2F) and other aromatic amine compounds. Other examples are: 3-[4-(1-Naphthyl)-phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN), 3-[4-(9-phenanthryl)-phenyl] -9-Phenyl-9H-carbazole (abbreviation: PCPPn), 3,3'-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP), 1,3-bis(N-carbazolyl) ) Benzene (abbreviation: mCP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), 3,6-bis(9H-carbazole-9- Base)-9-phenyl-9H-carbazole (abbreviation: PhCzGI), 2,8-bis(9H-carbazol-9-yl)-dibenzothiophene (abbreviation: Cz2DBT) and other amine compounds, carbazole compounds , thiophene compounds, furan compounds, fluorene compounds, triphenylene compounds, phenanthrene compounds, etc. Among the above-mentioned compounds, compounds having a pyrrole skeleton or an aromatic amine skeleton are preferable because of their high stability and high reliability. In addition, the compound having the above-mentioned skeleton has high hole transport properties and also contributes to lowering the driving voltage.

As the organic compound 131_2, a compound having a nitrogen-containing five-membered heterocyclic skeleton such as an imidazole skeleton, a triazole skeleton, or a tetrazole skeleton can be used. Specifically, for example, 3-(4-biphenyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 9-[ 4-(4,5-Diphenyl-4H-1,2,4-triazol-3-yl)phenyl]-9H-carbazole (abbreviation: CzTAZ1), 2,2',2"-(1 , 3,5-benzenetriyl) tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-benzene Base-1H-benzimidazole (abbreviation: mDBTBIm-II) and the like.

(chrysene)衍生物、菲衍生物、芘衍生物、二萘嵌苯衍生物、二苯乙烯衍生物、吖啶酮衍生物、香豆素衍生物、吩恶嗪衍生物、吩噻嗪衍生物等，例如可以使用如下物质中的任意物质。The guest material 132 in the light-emitting layer 130 is not particularly limited, and as the fluorescent compound, anthracene derivatives, naphthacene derivatives,

(chrysene) derivatives, phenanthrene derivatives, pyrene derivatives, perylene derivatives, stilbene derivatives, acridine derivatives, coumarin derivatives, phenoxazine derivatives, phenothiazine derivatives etc., for example, any of the following substances can be used.

(chrysene)-2，7，10，15-四胺(简称：DBC1)、香豆素30、N-(9，10-二苯基-2-蒽基)-N，9-二苯基-9H-咔唑-3-胺(简称：2PCAPA)、N-[9，10-双(1，1'-联苯-2-基)-2-蒽基]-N，9-二苯基-9H-咔唑-3-胺(简称：2PCABPhA)、N-(9，10-二苯基-2-蒽基)-N，N'，N'-三苯基-1，4-苯二胺(简称：2DPAPA)、N-[9，10-双(1，1'-联苯-2-基)-2-蒽基]-N，N'，N'-三苯基-1，4-苯二胺(简称：2DPABPhA)、9，10-双(1，1'-联苯-2-基)-N-[4-(9H-咔唑-9-基)苯基]-N-苯基蒽-2-胺(简称：2YGABPhA)、N，N，9-三苯基蒽-9-胺(简称：DPhAPhA)、香豆素6、香豆素545T、N，N'-二苯基喹吖酮(简称：DPQd)、红荧烯、2，8-二-叔丁基-5，11-双(4-叔丁苯基)-6，12-二苯基并四苯(简称：TBRb)、尼罗红、5，12-双(1，1'-联苯-4-基)-6，11-二苯基并四苯(简称：BPT)、2-(2-{2-[4-(二甲氨基)苯基]乙烯基}-6-甲基-4H-吡喃-4-亚基)丙二腈(简称：DCM1)、2-{2-甲基-6-[2-(2，3，6，7-四氢-1H，5H-苯并[ij]喹嗪-9-基)乙烯基]-4H-吡喃-4-亚基}丙二腈(简称：DCM2)、N，N，N'，N'-四(4-甲基苯基)并四苯-5，11-二胺(简称：p-mPhTD)、7，14-二苯基-N，N，N'，N'-四(4-甲基苯基)苊并[1，2-a]荧蒽-3，10-二胺(简称：p-mPhAFD)、2-{2-异丙基-6-[2-(1，1，7，7-四甲基-2，3，6，7-四氢-1H，5H-苯并[ij]喹嗪-9-基)乙烯基]-4H-吡喃-4-亚基}丙二腈(简称：DCJTI)、2-{2-叔丁基-6-[2-(1，1，7，7-四甲基-2，3，6，7-四氢-1H，5H-苯并[ij]喹嗪-9-基)乙烯基]-4H-吡喃-4-亚基}丙二腈(简称：DCJTB)、2-(2，6-双{2-[4-(二甲氨基)苯基]乙烯基}-4H-吡喃-4-亚基)丙二腈(简称：BisDCM)、2-{2，6-双[2-(8-甲氧基-1，1，7，7-四甲基-2，3，6，7-四氢-1H，5H-苯并[ij]喹嗪-9-基)乙烯基]-4H-吡喃-4-亚基}丙二腈(简称：BisDCJTM)、5，10，15，20-四苯基双苯并(tetraphenylbisbenzo)[5，6]茚并[1，2，3-cd:1'，2'，3'-lm]苝。Examples thereof include 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10 -Phenyl-9-anthryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), N,N'-diphenyl-N,N'-bis[4-(9 -Phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N'-bis(3-methylphenyl)-N,N' -Bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), N,N'-bis[4-(9- Phenyl-9H-fluoren-9-yl)phenyl]-N,N'-bis(4-tert-butylphenyl)pyrene-1,6-diamine (abbreviation: 1,6tBu-FLPAPrn), N,N '-Bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]N,N'-diphenyl-3,8-dicyclohexylpyrene-1,6-diamine (abbreviation: ch-1,6FLPAPrn), N,N'-bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine ( Abbreviation: YGA2S), 4-(9H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl) triphenylamine (abbreviation: YGAPA), 4-(9H-carbazole-9- base)-4'-(9,10-diphenyl-2-anthracenyl) triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthracene) base) phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), perylene, 2,5,8,11-tetra (tert-butyl) perylene (abbreviation: TBP), 4-(10-phenyl) -9-Anthracenyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPA), N,N"-(2-tert-butylanthracene-9,10- Diylbis-4,1-phenylene)bis[N,N',N'-triphenyl-1,4-phenylenediamine] (abbreviation: DPABPA), N,9-diphenyl-N- [4-(9,10-Diphenyl-2-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: 2PCAPPA), N-[4-(9,10-diphenyl-2 -Anthracenyl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA), N,N,N',N',N",N",N "',N"'-Octaphenyldibenzo[g,p]

(chrysene)-2,7,10,15-tetraamine (abbreviation: DBC1), coumarin 30, N-(9,10-diphenyl-2-anthryl)-N,9-diphenyl- 9H-carbazol-3-amine (abbreviation: 2PCAPA), N-[9,10-bis(1,1'-biphenyl-2-yl)-2-anthryl]-N,9-diphenyl- 9H-carbazol-3-amine (abbreviation: 2PCABPhA), N-(9,10-diphenyl-2-anthryl)-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9,10-bis(1,1'-biphenyl-2-yl)-2-anthryl]-N,N',N'-triphenyl-1,4- Phenylenediamine (abbreviation: 2DPABPhA), 9,10-bis(1,1'-biphenyl-2-yl)-N-[4-(9H-carbazol-9-yl)phenyl]-N-benzene Anthracene-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenylanthracene-9-amine (abbreviation: DPhAPhA), coumarin 6, coumarin 545T, N,N'-diphenyl Quinacridone (abbreviation: DPQd), rubrene, 2,8-di-tert-butyl-5,11-bis(4-tert-butylphenyl)-6,12-diphenyltetracene (abbreviation: TBRb), Nile Red, 5,12-bis(1,1'-biphenyl-4-yl)-6,11-diphenyltetracene (abbreviation: BPT), 2-(2-{2- [4-(Dimethylamino)phenyl]vinyl}-6-methyl-4H-pyran-4-ylidene)malononitrile (abbreviation: DCM1), 2-{2-methyl-6-[ 2-(2,3,6,7-Tetrahydro-1H,5H-benzo[ij]quinazin-9-yl)vinyl]-4H-pyran-4-ylidene}malononitrile (abbreviation: DCM2), N,N,N',N'-tetrakis(4-methylphenyl)naphthacene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N, N,N',N'-Tetrakis(4-methylphenyl)acenaphthene[1,2-a]fluoranthene-3,10-diamine (abbreviation: p-mPhAFD), 2-{2-isopropyl base-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinazin-9-yl)ethenyl] -4H-pyran-4-ylidene}malononitrile (abbreviation: DCJTI), 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3 , 6,7-Tetrahydro-1H,5H-benzo[ij]quinazin-9-yl)vinyl]-4H-pyran-4-ylidene}malononitrile (abbreviation: DCJTB), 2-( 2,6-bis{2-[4-(dimethylamino)phenyl]vinyl}-4H-pyran-4-ylidene)malononitrile (abbreviation: BisDCM), 2-{2,6-bis [2-(8-Methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinazin-9-yl)ethene base]-4 H-pyran-4-ylidene}malononitrile (abbreviation: BisDCJTM), 5,10,15,20-tetraphenylbisbenzo[5,6]indeno[1,2,3- cd: 1', 2', 3'-lm]perylene.

Note that, as shown in Table 1, the hydrocarbyl substituent contained in the first organic compound causes a decrease in the T1 energy level. Therefore, one embodiment of the present invention is more effective when the guest material has a function of converting triplet excitation energy into luminescence. Examples of materials having a function of converting triplet excitation energy into luminescence include phosphorescent materials and thermally activated delayed fluorescence (TADF) materials, which will be described below. Note that one embodiment of the present invention is particularly effective when the T1 level of these guest materials is high, specifically, when these guest materials exhibit emission peaks of 450 nm or more and 530 nm or less.

As the guest material 132 (phosphorescent compound), iridium-based, rhodium-based, platinum-based organometallic complexes or these metal complexes can be used, and in particular, organic iridium complexes such as iridium-based ortho metal complexes are preferred. Examples of the ortho-metallated ligands include 4H-triazole ligands, 1H-triazole ligands, imidazole ligands, pyridine ligands, pyrimidine ligands, pyrazine ligands, and isoquinoline ligands. Examples of the metal complex include platinum complexes having porphyrin ligands, and the like.

Examples of substances having an emission peak in the blue or green wavelength range include tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1, 2,4-Triazol-3-yl-κN2]phenyl-κC}iridium(III) (abbreviation: Ir(mpptz-dmp) ₃ ), tris(5-methyl-3,4-diphenyl-4H) -1,2,4-triazole) iridium (III) (abbreviation: Ir(Mptz) ₃ ), tris[4-(3-biphenyl)-5-isopropyl-3-phenyl-4H-1, 2,4-Triazole] iridium (III) (abbreviation: Ir(iPrptz-3b) ₃ ), tris[3-(5-biphenyl)-5-isopropyl-4-phenyl-4H-1,2 , 4-triazole] iridium (III) (abbreviation: Ir(iPr5btz) ₃ ) and other organometallic iridium complexes with 4H-triazole skeleton; tris[3-methyl-1-(2-methylphenyl) -5-Phenyl-1H-1,2,4-triazole]iridium(III) (abbreviation: Ir(Mptz1-mp) ₃ ), tris(1-methyl-5-phenyl-3-propyl- 1H-1,2,4-triazole) iridium (III) (abbreviation: Ir(Prptz1-Me) ₃ ) and other organometallic iridium complexes with 1H-triazole skeleton; fac-tri[1-(2,6 -Diisopropylphenyl)-2-phenyl-1H-imidazole]iridium(III) (abbreviation: Ir(iPrpmi) ₃ ), tris[3-(2,6-dimethylphenyl)-7- Methylimidazo[1,2-f]phenanthridineato]iridium(III) (abbreviation: Ir(dmpimpt-Me) ₃ ) and other organometallic iridium complexes with imidazole skeletons; and bis[2-( 4',6'-Difluorophenyl)pyridino-N, ^C2 ']iridium(III) tetrakis(1-pyrazolyl)borate (abbreviation: FIr6), bis[2-(4',6 '-Difluorophenyl)pyridine-N,C ² ']iridium(III) picolinate (abbreviation: FIrpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl ]pyridine-N,C ² '}iridium(III) picolinate (abbreviation: Ir(CF ₃ ppy) ₂ (pic)), bis[2-(4',6'-difluorophenyl)pyridine Organometallic iridium complexes such as root-N,C ² ']iridium(III) acetylacetone (abbreviation: FIr(acac)), etc., which use phenylpyridine derivatives with electron withdrawing groups as ligands. Among the materials listed above, organometal iridium complexes having nitrogen-containing five-membered heterocyclic skeletons such as 4H-triazole skeleton, 1H-triazole skeleton, or imidazole skeleton have high triplet excitation energy, high reliability, and high luminescence efficiency, so it is particularly preferred.

Examples of substances having a light emission peak in the wavelength range of green or yellow include tris(4-methyl-6-phenylpyrimidine)iridium(III) (abbreviation: Ir(mppm) ₃ ), tris(4-tert-butyl) -6-phenylpyrimidine) iridium (III) (abbreviation: Ir(tBuppm) ₃ ), (acetylacetonate)bis(6-methyl-4-phenylpyrimidine) iridium (III) (abbreviation: Ir (mppm) ₂ (acac)), (acetylacetonate) bis (6-tert-butyl-4-phenylpyrimidine) iridium (III) (abbreviation: Ir(tBuppm) ₂ (acac)), (acetylacetonate) bis[4 -(2-norbornyl)-6-phenylpyrimidine]iridium(III) (abbreviation: Ir(nbppm) ₂ (acac)), (acetylacetonate)bis[5-methyl-6-(2-methyl) phenyl)-4-phenylpyrimidine] iridium (III) (abbreviation: Ir (mpmppm) ₂ (acac)), (acetylacetonate) bis{4,6-dimethyl-2-[6-(2 , 6-dimethylphenyl)-4-pyrimidinyl-κN3]phenyl-κC} iridium (III) (abbreviation: Ir(dmppm-dmp) ₂ (acac)), (acetylacetonate) bis(4, 6-diphenylpyrimidine) iridium (III) (abbreviation: Ir(dppm) ₂ (acac)) and other organometallic iridium complexes with pyrimidine skeleton; (acetylacetonate) bis(3,5-dimethyl-2 -Phenylpyrazine) iridium (III) (abbreviation: Ir(mppr-Me) ₂ (acac)), (acetylacetonate) bis(5-isopropyl-3-methyl-2-phenylpyrazine) Iridium (III) (abbreviation: Ir(mppr-iPr) ₂ (acac)) and other organometallic iridium complexes with pyrazine skeleton; tris (2-phenylpyridine-N, C ² ') iridium (III) (abbreviation : Ir(ppy) ₃ ), bis(2-phenylpyridino-N,C ² ') iridium(III) acetylacetone (abbreviation: Ir(ppy) ₂ (acac)), bis(benzo[h]quinoline) Line) iridium (III) acetylacetone (abbreviation: Ir(bzq) ₂ (acac)), tris(benzo[h]quinoline) iridium (III) (abbreviation: Ir(bzq) ₃ ), tris(2-benzene) quinoline-N,C ^2' ) iridium (III) (abbreviation: Ir(pq) ₃ ), bis(2-phenylquinoline-N, C ² ') iridium (III) acetylacetone (abbreviation: Ir( pq) ₂ (acac)) and other organometallic iridium complexes with pyridine skeleton; bis(2,4-diphenyl-1,3-oxazole-N,C ² ') iridium (III) acetylacetone (abbreviation: Ir(dpo) ₂ (acac)), bis{2-[4'-(perfluorophenyl)phenyl]pyridine-N,C ² '}iridium(III) acetylacetone (abbreviation: Ir(p-PF- ph) ₂ (acac)), bis(2-phenylbenzothiazide) azole-N,C ² ') iridium (III) acetylacetone (abbreviation: Ir(bt) ₂ (acac)) and other organometallic iridium complexes; tris (acetylacetonate) (monophenanthroline) terbium (III) ( Abbreviation: Tb(acac) ₃ (Phen)) and other rare earth metal complexes. Among the materials listed above, organometallic iridium complexes having a pyrimidine skeleton are particularly preferable because they have remarkably high reliability and luminous efficiency.

Examples of substances having a light emission peak in the wavelength range of yellow or red include (diisobutyrylmethane)bis[4,6-bis(3-methylphenyl)pyrimidinide]iridium(III) (abbreviation: Ir (5mdppm) ₂ (dibm)), bis[4,6-bis(3-methylphenyl)pyrimidine](dipivaloylmethane) iridium(III) (abbreviation: Ir(5mdppm) ₂ (dpm) ), bis[4,6-bis (naphthalen-1-yl) pyrimidine radical] (dipivaloyl methane radical) iridium (III) (abbreviation: Ir (d1npm) ₂ (dpm)) and other organometallics with pyrimidine skeleton Iridium complex; (acetylacetonate) bis (2,3,5-triphenylpyrazine) iridium (III) (abbreviation: Ir(tppr) ₂ (acac)), bis (2,3,5-triphenylene) Phenylpyrazine) (dipivaloylmethane) iridium (III) (abbreviation: Ir(tppr) ₂ (dpm)), (acetylacetonate) bis[2,3-bis(4-fluorophenyl) Quinoxaline] iridium (III) (abbreviation: Ir(Fdpq) ₂ (acac)) and other organometallic iridium complexes with pyrazine skeleton; tris(1-phenylisoquinoline-N,C ^2' ) iridium (III) (abbreviation: Ir(piq) ₃ ), bis(1-phenylisoquinoline-N,C ^2' ) iridium (III) acetylacetone (abbreviation: Ir(piq) ₂ (acac)) and the like have pyridine Organometallic iridium complexes of the framework; platinum complexes such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum (II) (abbreviation: PtOEP); and three (1,3-diphenyl-1,3-propanedione (propanedionato)) (monophenanthroline) europium (III) (abbreviation: Eu(DBM) ₃ (Phen)), tris[1-(2- Thiophenoyl)-3,3,3-trifluoroacetone] (monophenanthroline) europium (III) (abbreviation: Eu(TTA) ₃ (Phen)) and other rare earth metal complexes. Among the materials listed above, organometallic iridium complexes having a pyrimidine skeleton are particularly preferable because they have remarkably high reliability and luminous efficiency. In addition, organometallic iridium complexes with a pyrazine skeleton can provide red light with good chromaticity.

As the light-emitting material contained in the light-emitting layer 130, any material can be used as long as it can convert triplet excitation energy into light-emitting. As the material capable of converting triplet excitation energy into light emission, in addition to phosphorescent materials, thermally activated delayed fluorescence (TADF) materials can be cited. Therefore, the term "phosphorescent material" in the specification may be interchanged with "thermally activated delayed fluorescent material". Note that the thermally activated delayed fluorescent material refers to a material that has a small difference between the triplet excitation energy level and the singlet excitation energy level and has a function of converting triplet excitation energy into singlet excitation energy through inverse intersystem crossing. Therefore, TADF materials can up-convert triplet excited states to singlet excited states (ie, inverse intersystem crossing) using minute thermal energy and can efficiently exhibit luminescence (fluorescence) from singlet excited states . TADF can be efficiently obtained in a state where the energy difference between the triplet excitation level and the singlet excitation level is preferably greater than 0 eV and 0.2 eV or less, and more preferably greater than 0 eV and 0.1 eV or less.

When the thermally activated delayed fluorescent material is composed of one material, for example, any of the following materials can be used.

First, fullerenes or derivatives thereof, acridine derivatives such as proflavin, eosin, and the like can be mentioned. In addition, metal-containing porphyrins including magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), palladium (Pd), or the like can be mentioned. Examples of the metal-containing porphyrin include protoporphyrin-tin fluoride complex (SnF ₂ (Proto IX)), mesoporphyrin-tin fluoride complex (SnF ₂ (Meso IX)), blood Porphyrin-tin fluoride complex (SnF ₂ (Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (SnF ₂ (Copro III-4Me)), octaethylporphyrin-tin fluoride complex (SnF ₂ (OEP)), protoporphyrin-tin fluoride complex (SnF ₂ (Etio I)), octaethylporphyrin-platinum chloride complex (PtCl ₂ (OEP)), etc.

As the thermally activated delayed fluorescent material composed of one material, a heterocyclic compound having a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring can also be used. Specifically, 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5 -Triazine (abbreviation: PIC-TRZ), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4, 6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 2-[4-(10H-phenoxazin-10-yl)phenyl]-4,6-diphenyl-1, 3,5-triazine (abbreviation: PXZ-TRZ), 3-[4-(5-phenyl-5,10-dihydrophenazine-10-yl)phenyl]-4,5-diphenyl- 1,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9-dimethyl-9H-acridin-10-yl)-9H-xanthene-9-one (abbreviation: ACRXTN ), bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviation: DMAC-DPS), 10-phenyl-10H, 10'H-spiro[acridine Pyridin-9,9'-anthracene]-10'-one (abbreviation: ACRSA). Since this heterocyclic compound has a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring, it has high electron-transporting properties and hole-transporting properties, which is preferable. Among skeletons having a π-electron-deficient heteroaromatic ring, diazine skeletons (pyrimidine skeleton, pyrazine skeleton, and pyridazine skeleton) and triazine skeletons are particularly preferred because of their high stability and high reliability. Among the skeletons having a π-electron-rich heteroaromatic ring, an acridine skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a furan skeleton and a pyrrole skeleton have high stability and reliability, so it is preferable to include one or more of these skeletons. multiple. As the pyrrole skeleton, an indole skeleton, a carbazole skeleton, or a 3-(9-phenyl-9H-carbazol-3-yl)-9H-carbazole skeleton is particularly preferable. Note that a substance in which a π-electron-rich type heteroaryl ring and a π-electron-deficient type heteroaryl ring are directly bonded is particularly preferable because of the donor property of the π-electron-rich type heteroaryl ring and the acceptor of the π-electron-deficient type heteroaryl ring Both the properties are increased, while the difference between the singlet excitation level and the triplet excitation level becomes smaller.

The light-emitting layer 130 may include materials other than the host material 131 and the guest material 132 .

衍生物、二苯并[g，p]

衍生物等的缩合多环芳香化合物，但是不局限于此。缩合多环芳香化合物的具体例子包括9，10-二苯基蒽(简称：DPAnth)、6，12-二甲氧基-5，11-二苯基

9，10-双(3，5-二苯基苯基)蒽(简称：DPPA)、9，10-二(2-萘基)蒽(简称：DNA)、2-叔丁基-9，10-二(2-萘基)蒽(简称：t-BuDNA)、9，9’-联蒽(简称：BANT)、9，9’-(二苯乙烯-3，3’-二基)二菲(简称：DPNS)、9，9’-(二苯乙烯-4，4’-二基)二菲(简称：DPNS2)、1，3，5-三(1-芘)苯(简称：TPB3)等。可以从上述物质及公知物质中选择一种或多种具有比上述客体材料132的激发能级高的单重激发能级或三重激发能级的物质。Examples of materials that can be used for the light-emitting layer 130 are anthracene derivatives, phenanthrene derivatives, pyrene derivatives,

Derivatives, dibenzo[g,p]

Condensed polycyclic aromatic compounds such as derivatives, but not limited thereto. Specific examples of the condensed polycyclic aromatic compounds include 9,10-diphenylanthracene (abbreviation: DPAnth), 6,12-dimethoxy-5,11-diphenyl

9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA), 9,10-bis(2-naphthyl)anthracene (abbreviation: DNA), 2-tert-butyl-9,10 -Bis(2-naphthyl)anthracene (abbreviation: t-BuDNA), 9,9'-bianthracene (abbreviation: BANT), 9,9'-(stilbene-3,3'-diyl)diphenanthrene (abbreviation: DPNS), 9,9'-(stilbene-4,4'-diyl)diphenanthrene (abbreviation: DPNS2), 1,3,5-tris(1-pyrene)benzene (abbreviation: TPB3) Wait. One or more substances having a singlet excitation energy level or a triplet excitation energy level higher than that of the guest material 132 described above may be selected from the above-mentioned substances and known substances.

For example, a compound having a heteroaromatic skeleton such as an oxadiazole derivative can be used for the light-emitting layer 130 . Specific examples thereof include 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis [5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3 , 4-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 4,4'-bis(5-methylbenzoxazol-2-yl) stilbene (abbreviation: CO11) : BzOs) and other heterocyclic compounds.

In addition, for example, a metal complex having a heterocyclic ring (eg, a zinc-based or aluminum-based metal complex) or the like can be used for the light-emitting layer 130 . As an example, a metal complex having a quinoline ligand, a benzoquinoline ligand, an oxazole ligand or a thiazole ligand can be mentioned. Specific examples thereof include metal complexes having a quinoline skeleton or a benzoquinoline skeleton, and the like, such as tris(8-hydroxyquinoline)aluminum(III) (abbreviation: Alq), tris(4-methyl-8-hydroxyquinoline) Lino) aluminum (III) (abbreviation: Almq ₃ ), bis(10-hydroxybenzo[h]quinoline) beryllium (II) (abbreviation: BeBq ₂ ), bis(2-methyl-8-hydroxyquinoline) (4-phenylphenol) aluminum (III) (abbreviation: BAlq), bis(8-hydroxyquinoline) zinc (II) (abbreviation: Znq), and the like. In addition, it is possible to use, for example, bis[2-(2-benzoxazolyl)phenol]zinc(II) (abbreviation: ZnPBO) or bis[2-(2-benzothiazolyl)phenol]zinc(II) (abbreviation: ZnPBO) : ZnBTZ) and other metal complexes having oxazolyl or thiazole ligands.

The light-emitting layer 130 may have a structure in which two or more layers are stacked. For example, in the case of forming the light-emitting layer 130 by stacking a first light-emitting layer and a second light-emitting layer in this order from the hole transport layer side, the first light-emitting layer is formed using a hole-transporting substance as a host material, and the electrons A transport substance is used as a host material to form the second light-emitting layer. The light-emitting materials contained in the first light-emitting layer and the second light-emitting layer may be the same or different. In addition, the material may have a function of presenting light of the same color or a function of presenting light of different colors. By using a light-emitting material having a function of exhibiting light of different colors from each other for the two light-emitting layers, light of a plurality of light-emitting colors can be simultaneously obtained. In particular, the light-emitting material of each light-emitting layer is preferably selected so that white light can be obtained by combining the light emitted by the two light-emitting layers.

In addition, the light-emitting layer 130 may be formed by vapor deposition (including vacuum vapor deposition), inkjet method, coating method, gravure printing, or the like. In addition to the above-mentioned materials, inorganic compounds such as quantum dots or polymer compounds (eg, oligomers, dendrimers, polymers) can also be used.

"Hole Injection Layer"

The hole injection layer 111 has a function of lowering the injection barrier of holes from one of the pair of electrodes (the electrode 101 or the electrode 102 ) to facilitate hole injection, and for example, a transition metal oxide, a phthalocyanine derivative, or an aromatic amine is used etc. to form. As a transition metal oxide, molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, manganese oxide, etc. are mentioned. As a phthalocyanine derivative, a phthalocyanine, a metal phthalocyanine, etc. are mentioned. As an aromatic amine, a benzidine derivative, a phenylenediamine derivative, etc. are mentioned. In addition, a polymer compound such as polythiophene and polyaniline can also be used, and a typical example thereof is poly(ethyldioxythiophene)/poly(styrenesulfonic acid) which is a self-doped polythiophene.

As the hole injection layer 111 , a layer containing a composite material of a hole transport material and a material having a property of accepting electrons from the hole transport material can be used. Alternatively, a stack of a layer containing a material having electron-accepting properties and a layer containing a hole-transporting material may be used. In a stationary state or in the presence of an electric field, charge transfer can take place between these materials. Examples of materials having electron-accepting properties include organic acceptors such as quinodimethane derivatives, tetrachlorobenzoquinone derivatives, and hexaazatriphenylene derivatives. Specifically, 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4 _- TCNQ), chloranil, 2,3,6, 7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN) and other compounds with electron withdrawing groups (halogen or cyano). In addition, transition metal oxides, such as oxides of Group 4 to Group 8 metals, may also be used. Specifically, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, rhenium oxide, and the like can be used. In particular, molybdenum oxide is preferably used because it is also stable in the atmosphere, has low hygroscopicity, and is easy to handle.

As the hole-transporting material, a material having a higher hole-transporting property than an electron-transporting property can be used, and a material having a hole mobility of 1×10 ^-6 cm ² /Vs or more is preferably used. Specifically, aromatic amines, carbazole derivatives, aromatic hydrocarbons, stilbene derivatives, etc., exemplified as the hole-transporting material that can be used for the light-emitting layer 130 can be used. In addition, the above-mentioned hole-transporting material may be a polymer compound.

Other examples of the hole transport material include aromatic hydrocarbons, for example, 2-tert-butyl-9,10-bis(2-naphthyl)anthracene (abbreviation: t-BuDNA), 2-tert-butyl Base-9,10-bis(1-naphthyl)anthracene, 9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA), 2-tert-butyl-9,10-bis( 4-phenylphenyl)anthracene (abbreviation: t-BuDBA), 9,10-bis(2-naphthyl)anthracene (abbreviation: DNA), 9,10-diphenylanthracene (abbreviation: DPAnth), 2- Tert-butylanthracene (abbreviation: t-BuAnth), 9,10-bis(4-methyl-1-naphthyl)anthracene (abbreviation: DMNA), 2-tert-butyl-9,10-bis[2-( 1-Naphthyl)phenyl]anthracene, 9,10-bis[2-(1-naphthyl)phenyl]anthracene, 2,3,6,7-tetramethyl-9,10-bis(1-naphthalene) base) anthracene, 2,3,6,7-tetramethyl-9,10-bis(2-naphthyl)anthracene, 9,9'-bianthracene, 10,10'-diphenyl-9,9' -Bianthracene, 10,10'-bis(2-phenylphenyl)-9,9'-bianthracene, 10,10'-bis[(2,3,4,5,6-pentaphenyl)benzene base]-9,9'-bianthracene, anthracene, tetracene, rubrene, perylene, 2,5,8,11-tetra(tert-butyl) perylene, etc. Other examples are pentacene, coronene, and the like. Aromatic hydrocarbons having a hole mobility of 1×10 ^-6 cm ² /Vs or more and having 14 to 42 carbon atoms are particularly preferable.

Aromatic hydrocarbons can also have a vinyl backbone. Examples of aromatic hydrocarbons with vinyl groups are 4,4'-bis(2,2-diphenylvinyl)biphenyl (abbreviation: DPVBi), 9,10-bis[4-(2,2-diphenylethylene) base) phenyl] anthracene (abbreviation: DPVPA) and the like.

Other examples are 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II), 4,4',4" -(Benzene-1,3,5-triyl)tris(dibenzofuran) (abbreviation: DBF3P-II), 1,3,5-tris(dibenzothiophen-4-yl)benzene (abbreviation: DBT3P -II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4-[4 -(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), 4-[3-(triphenylene-2-yl)phenyl ] Dibenzothiophene (abbreviation: mDBTPTp-II) and other thiophene compounds, furan compounds, fluorene compounds, triphenylene compounds, phenanthrene compounds, etc. Among the above-mentioned compounds, those having pyrrole skeleton, furan skeleton, thiophene skeleton and aromatic amine skeleton The compound is preferable because it has high stability and high reliability. In addition, the compound having the above-mentioned skeleton has high hole-transporting property, which also contributes to lowering the driving voltage.

"Hole Transport Layer"

The hole transport layer 112 is a layer containing a hole transport material, and can be formed using any hole transport material exemplified as the material of the hole injection layer 111 . In order for the hole transport layer 112 to have the function of transporting the holes injected into the hole injection layer 111 to the light emitting layer 130 , it is preferable that the highest occupied molecular orbital (HOMO) energy level of the hole transport layer 112 and the hole injection layer 111 The HOMO energy level is the same or close.

As the hole-transporting substance, a substance having a hole mobility of 1×10 ^-6 cm ² /Vs or more is preferably used. Note that any substances other than the above-mentioned substances may be used as long as the hole-transporting property is higher than the electron-transporting property. The layer containing the substance with high hole transport properties is not limited to a single layer, and two or more layers containing the substance may be stacked.

"Electron Transport Layer"

The electron transport layer 118 has a function of transporting electrons injected from the other of the pair of electrodes (the electrode 101 or the electrode 102 ) through the electron injection layer 119 to the light-emitting layer 130 . A material having a higher electron-transporting property than hole-transporting property can be used as the electron-transporting material, and a material having an electron mobility of 1×10 ^-6 cm ² /Vs or more is preferable. As a compound that easily accepts electrons (material having electron-transporting properties), π-electron-deficient heteroaromatic compounds such as nitrogen-containing heteroaromatic compounds, metal complexes, and the like can be used. Specifically, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, triazine derivatives, quinoxaline derivatives, and dibenzoquinoxaline, which are exemplified as electron-transporting materials that can be used in the light-emitting layer 130 can be mentioned. Derivatives, phenanthroline derivatives, triazole derivatives, benzimidazole derivatives, oxadiazole derivatives, etc. Preferably, the material has an electron mobility of 1×10 ^-6 cm ² /Vs or more. Note that, other than these substances, any substance having higher electron transport properties than hole transport properties may be used for the electron transport layer. The electron transport layer 118 is not limited to a single layer, and may include two or more stacked layers containing the above-mentioned substances.

In addition, as the metal complex having a heterocyclic ring, for example, a metal complex including a quinoline ligand, a benzoquinoline ligand, an oxazole ligand, or a thiazole ligand can be mentioned. Specific examples thereof include metal complexes having a quinoline skeleton or a benzoquinoline skeleton, and the like, such as tris(8-hydroxyquinoline)aluminum(III) (abbreviation: Alq), tris(4-methyl-8-hydroxyquinoline) Lino) aluminum (III) (abbreviation: Almq ₃ ), bis(10-hydroxybenzo[h]quinoline) beryllium (II) (abbreviation: BeBq ₂ ), bis(2-methyl-8-hydroxyquinoline) (4-phenylphenol) aluminum (III) (abbreviation: BAlq), bis(8-hydroxyquinoline) zinc (II) (abbreviation: Znq), and the like. In addition, for example, bis[2-(2-benzoxazolyl)phenol]zinc(II) (abbreviation: ZnPBO), bis[2-(2-benzothiazolyl)phenol]zinc(II) (abbreviation: ZnPBO), : ZnBTZ) and other metal complexes having oxazolyl or thiazole ligands.

A layer that controls the migration of electron carriers may also be provided between the electron transport layer 118 and the light emitting layer 130 . This layer is a layer formed by adding a small amount of a substance with high electron trapping property to the above-mentioned material with high electron transport property, and the carrier balance can be adjusted by suppressing the migration of electron carriers. Such a structure exerts a great effect on suppressing problems that occur when the electron-transporting property of the electron-transporting material is much higher than the hole-transporting property of the hole-transporting material, such as a reduction in the life of the device.

"Electron Injection Layer"

The electron injection layer 119 has a function of lowering the injection barrier of electrons from the electrode 102 to facilitate electron injection, and can be formed using, for example, Group 1 metals, Group 2 metals, or oxides, halides, carbonates, or the like of these metals. In addition, a composite material of the above-mentioned electron-transporting material and a material having the property of supplying electrons to the electron-transporting material can also be used. Examples of materials having electron donating properties include Group 1 metals, Group 2 metals, oxides of these metals, and the like. In particular, alkali metals, alkaline earth metals or compounds of these metals, such as lithium fluoride (LiF), sodium fluoride (NaF), cesium fluoride (CsF), calcium fluoride (CaF ₂ ) or lithium oxides can be used (LiO _x ). In addition, rare earth metal compounds such as erbium fluoride (ErF ₃ ) can be used. In addition, an electron salt may also be used for the electron injection layer 119 . As an example of this electron salt, what adds electrons to calcium oxide-aluminum oxide in a high concentration is mentioned. A substance that can be used for the electron transport layer 118 can be used for the electron injection layer 119 .

In addition, a composite material in which an organic compound and an electron donor (donor) are mixed may be used for the electron injection layer 119 . This composite material has excellent electron injection properties and electron transport properties because electrons are generated in organic compounds by electron donors. In this case, the organic compound is preferably a material excellent in transporting generated electrons. Specifically, for example, the substances constituting the electron transport layer 118 (eg, metal complexes, heteroaromatic compounds) as described above can be used. As the electron donor, a substance exhibiting electron-donating property to an organic compound can be used. Specifically, alkali metals, alkaline earth metals, and rare earth metals are preferably used, and examples thereof include lithium, sodium, cesium, magnesium, calcium, erbium, and ytterbium. In addition, alkali metal oxides or alkaline earth metal oxides are preferably used, and examples thereof include lithium oxides, calcium oxides, and barium oxides. In addition, Lewis bases such as magnesium oxide can also be used. In addition, organic compounds such as tetrathiafulvalene (abbreviation: TTF) can also be used.

In addition, the above-mentioned light-emitting layer, hole injection layer, hole transport layer, electron transport layer and electron injection layer can be formed by evaporation method (including vacuum evaporation method), inkjet method, coating method, gravure printing or the like. As the above-mentioned light-emitting layer, hole injection layer, hole transport layer, electron transport layer, and electron injection layer, in addition to the above-mentioned materials, inorganic compounds such as quantum dots or polymer compounds (for example, oligomers, dendrimers, etc.) can be used. polymers, polymers).

"Quantum Dots"

A quantum dot is a semiconductor nanocrystal whose size is several nm to several tens of nm, and includes about 1×10 ³ to 1×10 ⁶ atoms. The energy transfer of quantum dots depends on their size, and therefore, quantum dots formed of the same substance emit light whose emission wavelengths differ from each other depending on the size. Therefore, the emission wavelength can be easily adjusted by changing the size of the quantum dots used.

Since the peak width of the emission spectrum of the quantum dot is narrow, light emission with high color purity can be obtained. Furthermore, the theoretical internal quantum efficiency of quantum dots is considered to be about 100%, that is, substantially more than 25% of fluorescent organic compounds, and equal to that of phosphorescent organic compounds. Therefore, by using quantum dots as a light-emitting material, a light-emitting element with high light-emitting efficiency can be obtained. Furthermore, quantum dots, which are inorganic materials, are also excellent in substantial stability, so that a light-emitting element with a long lifetime can be obtained.

Materials for quantum dots include Group 14 elements, Group 15 elements, Group 16 elements, compounds containing a plurality of Group 14 elements, Group 4 to Group 14 elements and compounds of Group 16 elements, Group 2 elements Compounds of elements and Group 16 elements, Compounds of Group 13 elements and Group 15 elements, Compounds of Group 13 elements and Group 17 elements, Compounds of Group 14 elements and Group 15 elements, Group 11 elements and Compounds of Group 17 elements, iron oxide, titanium oxide, spinel chalcogenide, various semiconductor clusters, and the like.

Specifically, cadmium selenide, cadmium sulfide, cadmium telluride, zinc selenide, zinc oxide, zinc sulfide, zinc telluride, mercury sulfide, mercury selenide, mercury telluride, indium arsenide, and indium phosphide can be mentioned. , gallium arsenide, gallium phosphide, indium nitride, gallium nitride, indium antimonide, gallium antimonide, aluminum phosphide, aluminum arsenide, aluminum antimonide, lead selenide, lead telluride, lead sulfide, selenide Indium, indium telluride, indium sulfide, gallium selenide, arsenic sulfide, arsenic selenide, arsenic telluride, antimony sulfide, antimony selenide, antimony telluride, bismuth sulfide, bismuth selenide, bismuth telluride, silicon, silicon carbide , germanium, tin, selenium, tellurium, boron, carbon, phosphorus, boron nitride, boron phosphide, boron arsenide, aluminum nitride, aluminum sulfide, barium sulfide, barium selenide, barium telluride, calcium sulfide, selenide Calcium, calcium telluride, beryllium sulfide, beryllium selenide, beryllium telluride, magnesium sulfide, magnesium selenide, germanium sulfide, germanium selenide, germanium telluride, tin sulfide, tin sulfide, tin selenide, tin telluride, oxide Lead, copper fluoride, copper chloride, copper bromide, copper iodide, copper oxide, copper selenide, nickel oxide, cobalt oxide, cobalt sulfide, iron oxide, iron sulfide, manganese oxide, molybdenum sulfide, vanadium oxide, oxide Tungsten, tantalum oxide, titanium oxide, zirconium oxide, silicon nitride, germanium nitride, aluminum oxide, barium titanate, selenium zinc cadmium compounds, indium arsenic phosphorus compounds, cadmium selenide sulfur compounds, cadmium selenide tellurium compounds, Indium gallium arsenide compounds, indium gallium selenide compounds, indium selenide sulfur compounds, copper indium sulfur compounds, and combinations thereof, etc., but not limited thereto. In addition, so-called alloy-type quantum dots whose compositions are represented by arbitrary numbers can also be used. For example, since the alloy quantum dots of cadmium selenide sulfur can change the emission wavelength by changing the content ratio of elements, the alloy quantum dots of cadmium selenide and sulfur are one of the effective means to obtain blue light.

As the quantum dots, any of core-type quantum dots, core-shell (Core-Shell)-type quantum dots, and core-multishell (Core-Multishell)-type quantum dots can be used. The effects of defects or dangling bonds present on the nanocrystal surface can be reduced when the core is covered by other inorganic materials with wider band gaps. Since such a structure can greatly improve the quantum efficiency of light emission, it is preferable to use core-shell type or core-multi-shell type quantum dots. Examples of the material of the shell include zinc sulfide and zinc oxide.

Due to the high ratio of surface atoms, quantum dots are highly reactive and prone to aggregation. Therefore, the surface of the quantum dot is preferably attached with a protective agent or provided with a protective group. As a result, aggregation can be prevented and solubility in solvents can be improved. In addition, electrical stability can also be improved by reducing reactivity. Examples of protective agents (or protective groups) include polyoxyethylene alkyl groups such as lauryl alcohol polyoxyethylene ether, polyoxyethylene stearate (polyoxyethylene stearyl ether), and polyoxyethylene oleyl ether (polyoxyethylene oleyl ether). Ethers; trialkyl phosphines such as tripropyl phosphine, tributyl phosphine, trihexyl phosphine, trioctyl phosphine; polyoxyethylene n-octyl phenyl ether, polyoxyethylene n-nonyl phenyl ether Isopolyoxyethylene alkyl phenyl ethers; tertiary amines such as tris(n-hexyl)amine, tris(n-octyl)amine, tris(n-decyl)amine; tripropylphosphine oxide, tributyl Phosphine oxide, trihexylphosphine oxide, trioctylphosphine oxide, tridecylphosphine oxide and other organophosphorus compounds; polyethylene glycol diesters such as polyethylene glycol dilaurate and polyethylene glycol distearate ; Organic nitrogen compounds such as nitrogen-containing aromatic compounds such as pyridine, lutidine, collidine, quinoline; hexylamine, octylamine, decylamine, dodecylamine, tetradecylamine, hexadecane Aminoalkanes such as base amine and octadecylamine; dialkyl sulfides such as dibutyl sulfide; dialkyl sulfoxides such as dimethyl sulfoxide and dibutyl sulfoxide; sulfur-containing aromatic compounds such as thiophene, etc. Organic sulfur compounds; higher fatty acids such as palmitic acid, stearic acid, and oleic acid; ethanol; sorbitan fatty acid esters; fatty acid modified polyesters; tertiary amine modified polyurethanes; polyethyleneimine, etc.

The smaller the size of the quantum dot, the larger the band gap, so the size of the quantum dot is appropriately adjusted to obtain light of a desired wavelength. The smaller the crystal size, the more the emission of quantum dots migrates to the blue side (that is, the high-energy side). Therefore, by changing the size of the quantum dots, the emission wavelengths of the quantum dots can be adjusted to the ultraviolet region, the visible light region, and the infrared region. The wavelength range of the spectrum of the region. The size (diameter) of the quantum dots generally used is 0.5 nm to 20 nm, preferably 1 nm to 10 nm. In addition, the smaller the size distribution of the quantum dots, the narrower the emission spectrum, so that light emission with high color purity can be obtained. In addition, the shape of the quantum dots is not particularly limited, and may be spherical, rod-shaped, circular, or the like. In addition, since the quantum rods, which are rod-shaped quantum dots, have the function of expressing light with directivity, by using the quantum rods as a light-emitting material, a light-emitting element with higher external quantum efficiency can be obtained.

In most organic EL elements, quenching of the concentration of the light-emitting material is suppressed by dispersing the light-emitting material in the host material, thereby improving the light-emitting efficiency. The host material needs to have a singlet excitation energy level or a triplet excitation energy level higher than that of the light-emitting material. In particular, when a blue phosphorescent material is used as a light-emitting material, it is extremely difficult to develop a host material having a triplet excitation energy level higher than that of the blue phosphorescent material and having a long lifetime. Even when the light-emitting layer is formed of quantum dots without using a host material, the quantum dots can ensure light-emitting efficiency, so that a light-emitting element with a long service life can be obtained. When the light-emitting layer is composed of quantum dots, the quantum dots preferably have a core-shell structure (including a core-multishell structure).

When quantum dots are used as the light-emitting material of the light-emitting layer, the light-emitting layer has a thickness of 3 to 100 nm, preferably 10 to 100 nm, and the quantum dot content of the light-emitting layer is 1 to 100 vol.%. Note that the light-emitting layer is preferably composed of quantum dots. In addition, when forming a light-emitting layer in which the quantum dots are dispersed as a light-emitting material in a host material, the quantum dots may be dispersed in the host material or the host material and the quantum dots may be dissolved or dispersed in an appropriate liquid medium, and a wet method may be used. Method (spin coating method, casting method, dye coating method, blade coating method, roll coating method, ink jet method, printing method, spray method, curtain coating method, Langmuir Blodgett) law, etc.) For the light-emitting layer containing the phosphorescent material, in addition to the above-mentioned wet method, a vacuum evaporation method can be appropriately used.

As the liquid medium used in the wet process, for example, the following organic solvents can be used: ketones such as methyl ethyl ketone and cyclohexanone; fatty acid esters such as ethyl acetate; halogenated hydrocarbons such as dichlorobenzene; toluene, xylene, mesitylene, Aromatic hydrocarbons such as cyclohexylbenzene; aliphatic hydrocarbons such as cyclohexane, decalin, dodecane; dimethylformamide (DMF), dimethyl sulfoxide (DMSO), etc.

"A Pair of Electrodes"

The electrode 101 and the electrode 102 are used as the anode and the cathode of each light-emitting element. The electrode 101 and the electrode 102 can be formed using metals, alloys, conductive compounds, mixtures thereof, laminates, and the like.

One of the electrode 101 and the electrode 102 is preferably formed using a conductive material having a function of reflecting light. As an example of this electroconductive material, aluminum (Al), an alloy containing Al, etc. are mentioned. Examples of alloys containing Al include alloys containing Al and L (L represents one or more of titanium (Ti), neodymium (Nd), nickel (Ni), and lanthanum (La)). For example, an alloy containing An alloy of Al and Ti or an alloy containing Al, Ni and La. Aluminum has low resistivity and high light reflectivity. Since aluminum is contained in a large amount in the earth's crust and is inexpensive, the use of aluminum can reduce the manufacturing cost of the light-emitting element. In addition, an alloy of Ag, silver (Ag), and N can also be used (N represents yttrium (Y), Nd, magnesium (Mg), ytterbium (Yb), Al, Ti, gallium (Ga), zinc (Zn), indium One or more of (In), tungsten (W), manganese (Mn), tin (Sn), iron (Fe), Ni, copper (Cu), palladium (Pd), iridium (Ir) and gold (Au) a) etc. Examples of alloys containing silver include the following alloys: alloys containing silver, palladium, and copper; alloys containing silver and copper; alloys containing silver and magnesium; alloys containing silver and nickel; alloys containing silver and gold ; and alloys containing silver and ytterbium, etc. In addition, transition metals such as tungsten, chromium (Cr), molybdenum (Mo), copper, or titanium can be used.

Light emitted from the light emitting layer is extracted through the electrode 101 and/or the electrode 102 . Therefore, at least one of the electrode 101 and the electrode 102 is preferably formed using a conductive material having a function of transmitting light. As the conductive material, a conductive material having a visible light transmittance of 40% or more and 100% or less, preferably 60% or more and 100% or less, and a resistivity of 1×10 ^-2 Ω·cm or less can be used.

The electrode 101 and the electrode 102 may be formed using a conductive material having a function of transmitting light and a function of reflecting light. As the conductive material, a conductive material having a visible light reflectivity of 20% or more and 80% or less, preferably 40% or more and 70% or less, and a resistivity of 1×10 ^-2 Ω·cm or less can be used. For example, one or more of conductive metals, alloys and conductive compounds may be used. Specifically, indium tin oxide (hereinafter referred to as ITO), indium tin oxide (ITSO) containing silicon or silicon oxide, indium zinc oxide (indium zinc oxide), indium oxide containing titanium Metal oxides such as tin oxide, indium titanium oxide, and indium oxide including tungsten oxide and zinc oxide. A metal film having a thickness sufficient to transmit light (preferably a thickness of 1 nm or more and 30 nm or less) can be used. As the metal, Ag, an alloy of Ag and Al, an alloy of Ag and Mg, an alloy of Ag and Au, an alloy of Ag and Yb, and the like can be used.

In the present specification and the like, as a material that transmits light, a material that transmits visible light and has conductivity is used, such as the above-mentioned oxide conductors represented by ITO, oxide semiconductors, or organic conductors containing organic substances. Examples of the organic conductor containing an organic substance include a composite material in which an organic compound and an electron donor (donor) are mixed, a composite material in which an organic compound and an electron acceptor (acceptor) are mixed, and the like. In addition, inorganic carbon-based materials such as graphene can also be used. The resistivity of this material is preferably 1×10 ⁵ Ω·cm or less, and more preferably 1×10 ⁴ Ω·cm or less.

In addition, the electrode 101 and/or the electrode 102 may be formed by laminating a plurality of the above-mentioned materials.

In order to improve the light extraction efficiency, a material having a higher refractive index than the electrode may be formed in contact with the electrode having the function of transmitting light. Such a material may be a conductive material or a non-conductive material as long as it has a function of transmitting visible light. For example, in addition to the above-mentioned oxide conductors, oxide semiconductors and organic substances can be mentioned as examples of the material. As an example of an organic substance, the material used for a light-emitting layer, a hole injection layer, a hole transport layer, an electron transport layer, or an electron injection layer can be mentioned. In addition, an inorganic carbon-based material or a thin-film metal having a thickness sufficient to transmit light can be used. In addition, a stack having a thickness of several nm to several tens of nm can also be used.

When the electrode 101 or the electrode 102 is used as a cathode, the electrode preferably contains a material with a small work function (3.8 eV or less). For example, elements belonging to Group 1 or Group 2 in the periodic table (for example, alkali metals such as lithium, sodium, and cesium, alkaline earth metals such as calcium or strontium, and magnesium), alloys containing the above-mentioned elements (for example, Rare earth metals such as Ag—Mg or Al—Li), europium (Eu), or Yb, alloys containing the above-mentioned rare earth metals, alloys containing aluminum and silver, and the like.

When the electrode 101 or the electrode 102 is used as an anode, it is preferable to use a material with a large work function (4.0 eV or more).

The electrode 101 and the electrode 102 may be a laminate of a conductive material having a function of reflecting light and a conductive material having a function of transmitting light. In this case, the electrode 101 and the electrode 102 may have a function of adjusting the optical distance so that light of a desired wavelength from each light-emitting layer can be resonated and the light of the desired wavelength can be enhanced, which is preferable.

As a method of forming the electrode 101 and the electrode 102, a sputtering method, a vapor deposition method, a printing method, a coating method, a molecular beam epitaxy (MBE) method, a CVD method, a pulsed laser deposition method, an atomic Layer deposition (atomic layer deposition: ALD) method and the like.

"Substrate"

The light-emitting element of one embodiment of the present invention can be formed on a substrate of glass, plastic, or the like. As the order of stacking on the substrate, it may be stacked sequentially from the side of the electrode 101 or may be stacked sequentially from the side of the electrode 102 .

As a substrate on which the light-emitting element according to one embodiment of the present invention can be formed, for example, glass, quartz, plastic, or the like can be used. Alternatively, a flexible substrate can be used. The flexible substrate refers to a substrate that can be bent, such as a plastic substrate made of polycarbonate, polyarylate, and the like. In addition, a thin film, an inorganic vapor-deposited thin film, or the like can be used. Other materials may be used as long as they function as a support in the manufacturing process of the light-emitting element and the optical element or have a function of protecting the light-emitting element and the optical element.

In this specification and the like, for example, a light-emitting element can be formed using various substrates. The kind of substrate is not particularly limited. Examples of the substrate include semiconductor substrates (for example, single crystal substrates or silicon substrates), SOI substrates, glass substrates, quartz substrates, plastic substrates, metal substrates, stainless steel substrates, A substrate with a stainless steel foil, a tungsten substrate, a substrate with a tungsten foil, a flexible substrate, a laminated film, a paper or a base film containing a fibrous material, and the like. As examples of the glass substrate, there are barium borosilicate glass, aluminoborosilicate glass, soda lime glass, and the like. Examples of flexible substrates, lamination films, base films and the like include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone ( PES), polytetrafluoroethylene (PTFE) as the representative plastic substrate. As another example, resins, such as an acrylic resin, are mentioned. Alternatively, polypropylene, polyester, polyvinyl fluoride or polyvinyl chloride can be mentioned as examples. As another example, polyamide, polyimide, aramid, epoxy resin, inorganic vapor deposition film, paper, etc. are mentioned.

Alternatively, a flexible substrate may be used as the substrate, and light-emitting elements may be formed directly on the flexible substrate. Alternatively, a peeling layer may be provided between the substrate and the light-emitting element. The peeling layer may be used when a part or the whole of the light-emitting element formed on the peeling layer is separated from the substrate and transposed onto another substrate. At this time, the light-emitting element can be transposed on a substrate or a flexible substrate with low heat resistance. As the peeling layer, for example, a laminated structure of an inorganic film of a tungsten film and a silicon oxide film, or a structure in which a resin film such as polyimide is formed on a substrate can be used.

That is, it is also possible to form a light-emitting element using one substrate, and then transpose the light-emitting element onto another substrate. Examples of substrates on which light-emitting elements are transposed include cellophane substrates, stone substrates, wood substrates, cloth substrates (including natural fibers (for example, silk, cotton, hemp, etc.) ), synthetic fibers (eg, nylon, polyurethane, polyester), recycled fibers (eg, acetate, cupro, rayon, recycled polyester, etc.), leather backing, rubber backing, and the like. By using these substrates, a light-emitting element that is not easily damaged, a light-emitting element having high heat resistance, a light-emitting element that can be reduced in weight, or a light-emitting element that can be thinned can be formed.

In addition, for example, a field effect transistor (FET) may be formed on the above-mentioned substrate, and the light-emitting element 150 may be fabricated on an electrode electrically connected to the FET. Thereby, an active matrix display device in which the driving of the light-emitting element 150 is controlled by the FET can be manufactured.

The structure shown in this embodiment mode can be appropriately combined with any structure shown in other embodiment modes.

(Embodiment 2)

In this embodiment mode, a light-emitting element having a structure different from that shown in Embodiment Mode 1 and a light-emitting mechanism of the light-emitting element will be described with reference to FIGS. 4A to 4C . Portions having the same functions as those in FIG. 1A are shown using the same hatching in FIGS. 4A to 4C , and reference numerals are sometimes omitted. In addition, parts having the same function are denoted by the same reference numerals, and detailed descriptions thereof are sometimes omitted.

<Structure Example 1 of Light-Emitting Element>

FIG. 4A is a schematic cross-sectional view of the light emitting element 252 .

The light-emitting element 252 shown in FIG. 4A has a plurality of light-emitting cells (light-emitting cell 106 and light-emitting cell 110 in FIG. 4A ) between a pair of electrodes (electrode 101 and electrode 102 ). At least one light-emitting unit has the same structure as the EL layer 100 . In addition, the light-emitting unit 106 and the light-emitting unit 110 may have the same structure or different structures.

In addition, in the light-emitting element 252 shown in FIG. 4A , the light-emitting unit 106 and the light-emitting unit 110 are stacked, and the charge generating layer 115 is provided between the light-emitting unit 106 and the light-emitting unit 110 . For example, it is preferable to use the same structure as the EL layer 100 for the light emitting unit 106 .

The light-emitting element 252 includes the light-emitting layer 140 and the light-emitting layer 170 . The light emitting unit 106 includes a hole injection layer 111 , a hole transport layer 112 , an electron transport layer 113 and an electron injection layer 114 in addition to the light emitting layer 170 . In addition to the light emitting layer 140 , the light emitting unit 110 further includes a hole injection layer 116 , a hole transport layer 117 , an electron transport layer 118 and an electron injection layer 119 .

The charge generation layer 115 may have a structure in which an acceptor substance as an electron acceptor is added to a hole transport material, or a structure in which a donor substance as an electron donor is added to the electron transport material. In addition, these two structures may be stacked.

When the charge generation layer 115 includes a composite material of an organic compound and an acceptor substance, a composite material that can be used for the hole injection layer 111 described in Embodiment 1 may be used as the composite material. As the organic compound, various compounds such as aromatic amine compounds, carbazole compounds, aromatic hydrocarbons, and polymer compounds (oligomers, dendrimers, polymers, etc.) can be used. It is preferable to use an organic compound whose hole mobility is 1×10 ^-6 cm ² /Vs or more. However, any other material may be used as long as the hole transport property is higher than the electron transport property. Since the composite material of the organic compound and the acceptor substance has good carrier injection properties and carrier transport properties, low-voltage driving or low-current driving can be realized. Note that when the surface of the anode side of the light-emitting unit is in contact with the charge-generating layer 115, the charge-generating layer 115 may also function as a hole injection layer or a hole transport layer of the light-emitting unit, so it can also be used in the light-emitting unit. No hole injection layer or hole transport layer is included. Note that when the surface on the cathode side of the light-emitting unit is in contact with the charge-generating layer 115, the charge-generating layer 115 may also function as an electron injection layer or electron transport layer of the light-emitting unit, so it may not be included in the light-emitting unit. Electron injection layer or electron transport layer.

The charge generation layer 115 may have a laminated structure of a layer containing a composite material of an organic compound and an acceptor substance and a layer containing other materials. For example, the charge generation layer 115 may be formed by combining a layer containing a composite material of an organic compound and an acceptor substance, and a layer containing one compound selected from electron donating substances and a compound having high electron transport properties. In addition, the charge generation layer 115 may be formed by combining a layer containing a composite material of an organic compound and an acceptor substance and a layer containing a transparent conductive material.

The charge generation layer 115 provided between the light emitting unit 106 and the light emitting unit 108 only has the ability to inject electrons into one light emitting unit and inject holes into the other light emitting unit when a voltage is applied between the electrode 101 and the electrode 102. structure. For example, in FIG. 6A , when a voltage is applied such that the potential of the electrode 101 is higher than that of the electrode 102 , the charge generation layer 115 injects electrons into the light emitting unit 106 and injects holes into the light emitting unit 108 .

From the viewpoint of light extraction efficiency, the charge generation layer 115 preferably has visible light transmittance (specifically, visible light transmittance of 40% or more). The charge generation layer 115 functions even if its conductivity is lower than that of the pair of electrodes (electrodes 101 and 102 ).

By forming the charge generation layer 115 using any of the above-mentioned materials, it is possible to suppress an increase in the driving voltage when the light-emitting layers are stacked.

A light-emitting element having two light-emitting units is described in FIG. 4A , but the same structure can be applied to a light-emitting element in which three or more light-emitting units are stacked. As shown in the light-emitting element 252, by arranging a plurality of light-emitting cells between a pair of electrodes in such a manner that they are separated by a charge-generating layer, it is possible to provide high-luminance light emission with a longer lifetime while maintaining a low current density light-emitting element. In addition, a light-emitting element with low power consumption can be realized.

In addition, by applying the structure shown in Embodiment 1 to at least one of the plurality of cells, a light-emitting element with high luminous efficiency and a light-emitting element with high reliability can be provided.

The light-emitting layer of the light-emitting unit 110 preferably contains a phosphorescent compound. That is, it is preferable that the light-emitting layer 140 included in the light-emitting unit 110 contains a phosphorescent compound, and the light-emitting layer 170 included in the light-emitting unit 106 has the structure of the light-emitting layer 130 shown in Embodiment 1. An example of the structure of the light-emitting element 252 at this time will be described below.

As shown in FIG. 4B , the light-emitting layer 140 included in the light-emitting unit 110 includes a host material 141 and a guest material 142 . The host material 141 includes an organic compound 141_1 and an organic compound 141_2. Hereinafter, the guest material 142 contained in the light-emitting layer 140 will be described as a phosphorescent compound.

"Light Emitting Mechanism of Light Emitting Layer 140"

Next, the light-emitting mechanism of the light-emitting layer 140 will be described below.

The organic compound 141_1 and the organic compound 141_2 in the light-emitting layer 140 preferably form an exciplex.

The combination of the organic compound 141_1 and the organic compound 141_2 may be any combination capable of forming an exciplex, and it is preferable that one of them is a compound having hole transport properties and the other is a compound having electron transport properties.

FIG. 4C shows the energy level correlation of the organic compound 141_1 , the organic compound 141_2 , and the guest material 142 in the light-emitting layer 140 . In addition, the terms and reference numerals in FIG. 4C are shown below:

Host (141_1): organic compound 141_1 (host material);

Host (141_2): organic compound 141_2 (host material);

Guest (142): guest material 142 (phosphorescent compound);

S _PH1 : the S1 energy level of the organic compound 141_1 (host material);

T _PH1 : the T1 energy level of the organic compound 141_1 (host material);

S _PH2 : the S1 energy level of the organic compound 141_2 (host material);

T _PH2 : the T1 energy level of the organic compound 141_2 (host material);

T _PG : the T1 energy level of the guest material 142 (phosphorescent compound);

S _PE : the S1 energy level of the exciplex; and

T _PE : T1 level of the exciplex.

When one of the organic compound 141_1 and the organic compound 141_2 accepts holes and the other accepts electrons, an exciplex is rapidly formed (refer to the route E ₁ of FIG. 4C ). Alternatively, when one of the organic compounds becomes an excited state, an exciplex is rapidly formed by interacting with another organic compound. The excitation energy level (S _PE or T _PE ) of the exciplex is lower than the S1 energy level (S _PH1 and S _PH2 ) of the host materials (organic compound 141_1 and organic compound 141_2) forming the exciplex, so it can be used at a lower level. A low excitation energy forms an excited state of the host material 141 . Thereby, the driving voltage of the light-emitting element can be reduced.

Then, luminescence is obtained by transferring the energy of the S _PE and T _PE of the exciplex to the T1 level of the guest material 142 (phosphorescent compound) (see paths E ₂ and E ₃ in FIG. 4C ).

The T1 energy level (T _PE ) of the exciplex is preferably higher than the T1 energy level (T _PG ) of the guest material 142 and is the T1 energy level of each organic compound (organic compound 141_1 and organic compound 141_2) forming the exciplex (T _PH1 and T _PH2 ) or less. Thereby, the singlet excitation energy and triplet excitation energy of the exciplex formed can be transferred from the S1 level (S _PE ) and the T1 level (T _PE ) of the exciplex to the T1 energy of the guest material 142 level (T _PG ).

In order for the organic compound 141_1 and the organic compound 141_2 to efficiently form an exciplex, it is preferable to satisfy the following conditions: the HOMO level of one of the organic compound 141_1 and the organic compound 141_2 is higher than the HOMO level of the other, and the organic compound 141_1 and the organic compound The LUMO level of one of 141_2 is higher than that of the other.

When the combination of the organic compound 141_1 and the organic compound 141_2 is a combination of a compound having hole transport properties and a compound having electron transport properties, the carrier balance can be easily controlled by the mixing ratio thereof. Specifically, the compound having hole transport properties: the compound having electron transport properties is preferably in the range of 1:9 to 9:1 (weight ratio). In addition, with this structure, the carrier balance can be easily controlled, whereby the carrier recombination region can also be easily controlled.

Note that in this specification and the like, the process of the above-mentioned routes E ₁ to E ₃ is sometimes referred to as ExTET (Exciplex-Triplet Energy Transfer: Exciplex-Triplet Energy Transfer). In other words, in the light-emitting layer 140 , excitation energy is supplied from the exciplex to the guest material 142 . In this case, the efficiency of inverse intersystem transition from T _PE to S _PE and the quantum yield of light emission from S _PE are not necessarily high, so more materials can be selected.

When ExTET is used, a highly reliable light-emitting element with high luminous efficiency can be obtained.

Note that the light-emitting layer 170 may have any of the structure of the light-emitting layer 130 and the structure of the light-emitting layer 140 shown in Embodiment Mode 1.

Note that in each of the above structures, the light-emitting colors of the guest materials used for the light-emitting unit 106 and the light-emitting unit 110 may be the same or different. When the light-emitting unit 106 and the light-emitting unit 110 use the same guest material exhibiting the same color, the light-emitting element 252 can exhibit high luminance with a small current value, which is preferable. When guest materials emitting light of different colors are used for the light-emitting unit 106 and the light-emitting unit 110, the light-emitting element 252 can exhibit multicolor light emission, which is preferable. At this time, when a plurality of light-emitting materials with different light-emitting wavelengths are used in one or both of the light-emitting layer 140 and the light-emitting layer 170 , light having different light-emitting peaks is combined with light emitted from the light-emitting element 252 . In other words, the emission spectrum of the light-emitting element 252 has at least two maxima.

The above structure is suitable for obtaining white light emission. By making the light of the light-emitting layer 140 and the light-emitting layer 170 complementary colors, white light emission can be obtained. In particular, it is preferable to select the guest material so as to realize white light emission with high color rendering properties, or at least red, green, and blue light emission.

In addition, at least one of the light-emitting layer 140 and the light-emitting layer 170 may be further divided into layers, and the divided layers may contain different light-emitting materials. That is, at least one of the light-emitting layer 140 and the light-emitting layer 170 may be formed of two or more layers. For example, in the case of forming a light-emitting layer by stacking a first light-emitting layer and a second light-emitting layer in this order from the hole transport layer side, the first light-emitting layer is formed using a material having hole transport properties as a host material, and the second light-emitting layer is formed The light-emitting layer is formed using an electron-transporting material as a host material. In this case, the light-emitting materials contained in the first light-emitting layer and the second light-emitting layer may be the same or different materials. In addition, the above-mentioned materials may have a function of exhibiting light emission of the same color or a function of exhibiting light emission of different colors. By using a plurality of light-emitting materials exhibiting light emission of different colors, white light emission with high color rendering properties composed of three primary colors or four or more light emission colors can be obtained.

This embodiment mode can be appropriately combined with any other embodiment mode.

(Embodiment 3)

In this embodiment, a light-emitting device using the light-emitting element described in Embodiment 1 and Embodiment 2 will be described with reference to FIGS. 5A and 5B .

5A is a top view of the light emitting device, and FIG. 5B is a cross-sectional view taken along lines A-B and C-D in FIG. 5A . This light-emitting device includes a driver circuit portion (source side driver circuit) 601 for controlling light emission of the light emitting element, a pixel portion 602 and a driver circuit portion (gate side driver circuit) 603 indicated by dotted lines. In addition, reference numeral 604 is a sealing substrate, reference numeral 625 is a desiccant, and reference numeral 605 is a sealing agent. The portion surrounded by the sealant 605 is the space 607 .

Note that the guide wiring 608 is a wiring for transmitting signals input to the source side driver circuit 601 and the gate side driver circuit 603, and receives video signals from a flexible printed circuit (FPC) 609 serving as an external input terminal, Clock signal, start signal, reset signal, etc. Although only the FPC is illustrated here, the FPC may also be mounted with a printed wiring board (PWB). The light emitting device in this specification includes not only a light emitting device main body but also a light emitting device mounted with an FPC or a PWB within its category.

Next, the cross-sectional structure of the light-emitting device described above will be described with reference to FIG. 5B . A driver circuit portion and a pixel portion are formed on the element substrate 610 . Here, the source side driver circuit 601 serving as the driver circuit portion and one pixel in the pixel portion 602 are shown.

In the source side driver circuit 601, a CMOS circuit in which an n-channel type TFT 623 and a p-channel type TFT 624 are combined is formed. The driver circuit can also be formed using various CMOS circuits, PMOS circuits, or NMOS circuits. Although the driver-integrated type in which the driver circuit is formed on the substrate is shown in this embodiment mode, the driver circuit does not necessarily need to be formed on the substrate, and may be formed outside the substrate.

The pixel portion 602 includes a plurality of pixels including a switching TFT 611 , a current control TFT 612 , and a first electrode 613 electrically connected to the drain of the current control TFT 612 . Note that the insulator 614 is formed so as to cover the end portion of the first electrode 613 . The insulator 614 may be formed using a positive type photosensitive resin film.

In order to improve the coverage of the film formed on the insulator 614, the upper end portion or the lower end portion of the insulator 614 is formed into a curved surface having a curvature. For example, when a photosensitive acrylic resin is used as the material of the insulator 614, it is preferable that only the upper end portion of the insulator 614 has a curved surface. The curvature radius of the curved surface is preferably 0.2 μm or more and 0.3 μm or less. As the insulator 614, a negative type photosensitive material or a positive type photosensitive material can be used.

An EL layer 616 and a second electrode 617 are formed on the first electrode 613 . As the material of the first electrode 613 used as the anode, a material having a large work function is preferably used. For example, in addition to an ITO film, an indium tin oxide film containing silicon, an indium oxide film containing 2 wt % or more and 20 wt % or less of zinc oxide, a titanium nitride film, a chromium film, a tungsten film, a Zn film, a Pt film, etc. In addition to the layered film, a laminated film including a titanium nitride film and a film mainly composed of aluminum, a three-layer structure film including a titanium nitride film, a film mainly composed of aluminum, and a titanium nitride film, and the like can be used. When the laminated structure is adopted, the wiring resistance is also low, a good ohmic contact can be obtained, and it can be used as an anode.

The EL layer 616 is formed by any of various methods such as vapor deposition using a vapor deposition mask, ink jet method, and spin coating. As another material contained in the EL layer 616, a low molecular compound or a high molecular compound (including an oligomer or a dendrimer) can also be used.

As the material of the second electrode 617 formed on the EL layer 616 and used as a cathode, a material with a small work function (Al, Mg, Li, Ca, or their alloys and compounds, MgAg, MgIn, AlLi, etc.) is preferably used. When light generated in the EL layer 616 is transmitted through the second electrode 617, it is preferable to use a thin metal film and a transparent conductive film (ITO, zinc oxide containing 2 wt % or more and 20 wt % or less) as the second electrode 617 Laminates of indium oxide, indium tin oxide containing silicon, zinc oxide (ZnO), etc.).

Note that the light emitting element 618 is formed of the first electrode 613 , the EL layer 616 and the second electrode 617 . The light-emitting element 618 preferably has the structures shown in Embodiments 1 and 2. In the light-emitting device of the present embodiment, the pixel portion including a plurality of light-emitting elements may include both the light-emitting elements having the structures described in Embodiments 1 and 2 and light-emitting elements having different structures.

By bonding the sealing substrate 604 and the element substrate 610 with the sealing agent 605 , a light-emitting element 618 is provided in the space 607 surrounded by the element substrate 610 , the sealing substrate 604 , and the sealing agent 605 . The space 607 is filled with filler. The filler may also be an inert gas (nitrogen, argon, etc.) or a resin and/or a desiccant.

As the sealant 605, epoxy resin or glass frit is preferably used. These materials are preferably materials that do not permeate moisture or oxygen as much as possible. As the sealing substrate 604, a glass substrate, a quartz substrate, or a plastic substrate formed of fiber reinforced plastic (FRP), polyvinyl fluoride (PVF), polyester or acrylic resin, or the like can be used.

A light-emitting device including the light-emitting elements described in Embodiments 1 and 2 can be obtained by the above method.

<Structure Example 2 of Light-Emitting Device>

6A and 6B each show an example of a display device including a light-emitting element exhibiting white light emission and a coloring layer (color filter).

6A shows a substrate 1001 , a base insulating film 1002 , a gate insulating film 1003 , gate electrodes 1006 , 1007 , and 1008 , a first interlayer insulating film 1020 , a second interlayer insulating film 1021 , a peripheral portion 1042 , and a pixel portion 1040 , the driving circuit portion 1041, the first electrodes 1024W, 1024R, 1024G, 1024B of the light emitting element, the partition wall 1026, the EL layer 1028, the second electrode 1029 of the light emitting element, the sealing substrate 1031, the sealant 1032, and the like.

In FIGS. 6A and 6B , the colored layers (the red colored layer 1034R, the green colored layer 1034G, and the blue colored layer 1034B) are provided on the transparent substrate 1033 . In addition, a black layer (black matrix) 1035 may also be provided. The transparent substrate 1033 provided with the colored layer and the black layer is aligned and fixed on the substrate 1001 . Note that the colored layer and the black layer are covered by the cover layer 1036 . In FIG. 5A , light emitted from some light-emitting layers does not pass through the colored layers, while light emitted from other light-emitting layers passes through the colored layers. Since the light that does not pass through the coloring layer is white and the light that passes through any one of the coloring layers is red, blue, and green, an image can be represented by pixels of four colors.

FIG. 6B shows an example in which a red colored layer 1034R, a green colored layer 1034G, and a blue colored layer 1034B are formed between the gate insulating film 1003 and the first interlayer insulating film 1020 . As shown in FIG. 6B , a colored layer may also be provided between the substrate 1001 and the sealing substrate 1031 .

The light-emitting device described above has a structure in which light is extracted from the side of the substrate 1001 on which the TFTs are formed (bottom emission structure), but may also have a structure in which light is extracted from the side of the sealing substrate 1031 (top emission structure).

<Structure Example 3 of Light-Emitting Device>

7 is a cross-sectional view of a light emitting device having a top emission structure. In this case, a substrate 1001 that does not transmit light can be used. The steps up to the manufacture of the connecting electrode connecting the TFT and the anode of the light-emitting element are performed in the same manner as in the light-emitting device having the bottom emission structure. Then, a third interlayer insulating film 1037 is formed so as to cover the electrodes 1022 . The insulating film may also have a flattening function. The third interlayer insulating film 1037 can be formed using the same material as the second interlayer insulating film 1021 or other various materials.

Although the lower electrodes 1025W, 1025R, 1025G, and 1025B of the light-emitting element are all anodes here, they may also be cathodes. In addition, in the light-emitting device having the top emission structure shown in FIG. 7 , it is preferable that the lower electrodes 1025W, 1025R, 1025G, and 1025B are reflective electrodes. Note that the second electrode 1029 preferably has a function of emitting light and transmitting light. Preferably, a microcavity structure is used between the second electrode 1029 and the lower electrodes 1025W, 1025R, 1025G, and 1025B, so that light of a specific wavelength can be amplified. The EL layer 1028 is formed so as to have the same structure as that described in Embodiment 2, and white light emission can be obtained.

In FIGS. 6A , 6B and 7 , the structure of the EL layer capable of obtaining white light emission may be realized by using a plurality of light-emitting layers or using a plurality of light-emitting units. Note that the structure for obtaining white light emission is not limited to this.

In the case of adopting the top emission structure as shown in FIG. 7 , sealing can be performed using a sealing substrate 1031 provided with coloring layers (red coloring layer 1034R, green coloring layer 1034G, blue coloring layer 1034B). The sealing substrate 1031 may also be provided with a black layer (black matrix) 1035 between pixels. The coloring layers (red coloring layer 1034R, green coloring layer 1034G, blue coloring layer 1034B) and black layer (black matrix) 1035 may be covered with a cover layer. Note that a light-transmitting substrate is used as the sealing substrate 1031 .

Although an example in which full-color display is performed in four colors of red, green, blue, and white is shown here, it is not limited to this, and three colors of red, green, and blue, or red, The four colors of green, blue and yellow are displayed in full color.

By the above method, a light-emitting device including the light-emitting element described in Embodiments 3 and 4 can be obtained.

This embodiment mode can be appropriately combined with any other embodiment mode.

(Embodiment 4)

In this embodiment, a specific example of a display device including the light-emitting element described in Embodiment 1 and Embodiment 2 will be described. The display device described below includes two elements, a reflective liquid crystal element and a light-emitting element. The display device is capable of displaying in a transmissive mode and a reflective mode. As the light-emitting element, the light-emitting elements described in Embodiments 1 and 2 are preferably used.

<Configuration Example 1 of Display Device>

FIG. 8A is a block diagram showing an example of the configuration of the display device 400 . The display device 400 includes a plurality of pixels 410 arranged in a matrix in the display unit 362 . Display device 400 also includes circuit GD and circuit SD. In addition, the display device 400 includes a plurality of wirings G1, a plurality of wirings G2, a plurality of wirings ANO, and a plurality of wirings CSCOM electrically connected to the plurality of pixels 410 and the circuit GD arranged in the direction R. In addition, the display device 400 includes a plurality of wirings S1 and a plurality of wirings S2 electrically connected to the plurality of pixels 410 and the circuit SD arranged in the direction C.

The pixel 410 includes a reflective liquid crystal element and a light-emitting element. In the pixel 410, the liquid crystal element and the light emitting element partially overlap each other.

FIG. 8B1 shows an example of the structure of the electrode 311 b included in the pixel 410 . The electrode 311 b is used as a reflective electrode of the liquid crystal element in the pixel 410 . The electrode 311b has an opening 451 .

In FIG. 8B1 , the light emitting element 360 located in the region overlapping with the electrode 311 b is shown by a dotted line. The light-emitting element 360 overlaps with the opening 451 included in the electrode 311b. Thereby, the light emitted from the light emitting element 360 is emitted to the display surface side through the opening 451 .

In FIG. 8B1, adjacent pixels 410 in the direction R correspond to different colors. As shown in FIG. 8B1 , the openings 451 in two adjacent pixels in the direction R are preferably arranged at different positions of the electrode 311b so as not to be arranged in a row. Thereby, the two light-emitting elements 360 can be arranged separately, so that light emitted from the light-emitting elements 360 can be prevented from being incident on the coloring layers in the adjacent pixels 410 (this phenomenon is also referred to as crosstalk). In addition, since two adjacent light-emitting elements 360 can be arranged separately, even if the EL layers of the light-emitting elements 360 are separately fabricated using a shadow mask or the like, a high-resolution display device can be realized.

In addition, the arrangement shown in FIG. 8B2 may also be employed.

When the ratio of the total area of the opening 451 to the total area other than the opening is too large, the display using the liquid crystal element becomes dark. When the ratio of the total area of the opening 451 to the total area other than the opening is too small, the display using the light emitting element 360 becomes dark.

When the area of the opening 451 in the electrode 311b used as the reflective electrode is too small, the extraction efficiency of the light emitted by the light emitting element 360 becomes low.

The opening 451 may have a polygonal, quadrangular, oval, circular, cross, strip, slit, or checkered shape. The openings 451 may be arranged close to adjacent pixels. Preferably, the openings 451 are arranged close to other pixels displaying the same color, whereby generation of crosstalk can be suppressed.

[Example of circuit configuration]

FIG. 9 is a circuit diagram showing an example of the structure of the pixel 410 . FIG. 9 shows two adjacent pixels 410 .

The pixel 410 includes a switch SW1, a capacitor C1, a liquid crystal element 340, a switch SW2, a transistor M, a capacitor C2, a light-emitting element 360, and the like. The pixel 410 is electrically connected to the wiring G1, the wiring G2, the wiring ANO, the wiring CSCOM, the wiring S1, and the wiring S2. FIG. 12 also shows the wiring VCOM1 electrically connected to the liquid crystal element 340 and the wiring VCOM2 electrically connected to the light emitting element 360 .

FIG. 9 shows an example in which transistors are used for the switch SW1 and the switch SW2.

The gate of the switch SW1 is connected to the wiring G1. One of the source and drain of the switch SW1 is connected to the wiring S1 , and the other of the source and the drain is connected to one electrode of the capacitor C1 and one electrode of the liquid crystal element 340 . The other electrode of the capacitor C1 is connected to the wiring CSCOM. The other electrode of the liquid crystal element 340 is connected to the wiring VCOM1.

The gate of the switch SW2 is connected to the wiring G2. One of the source and drain of the switch SW2 is connected to the wiring S2, and the other of the source and the drain is connected to one electrode of the capacitor C2 and the gate of the transistor M. The other electrode of the capacitor C2 is connected to one of the source and drain of the transistor M and the wiring ANO. The other of the source and drain of the transistor M is connected to one electrode of the light-emitting element 360 . The other electrode of the light-emitting element 360 is connected to the wiring VCOM2.

FIG. 10A shows an example in which the transistor M includes two interconnected gate electrodes sandwiching a semiconductor. This structure can increase the amount of current that the transistor M can flow.

A signal for switching the ON/OFF state of the switch SW1 can be supplied to the wiring G1. A predetermined potential can be supplied to the wiring VCOM1. A signal for controlling the alignment state of the liquid crystal that the liquid crystal element 340 has can be supplied to the wiring S1 . A predetermined potential can be supplied to the wiring CSCOM.

A signal for switching the on/off state of the switch SW2 can be supplied to the wiring G2. The wiring VCOM2 and the wiring ANO can be supplied with a potential that generates a potential difference for causing the light-emitting element 360 to emit light. A signal for switching the conduction state of the transistor M may be supplied to the wiring S2.

In the pixel 410 shown in FIGS. 10A and 10B , for example, when displaying in the reflective mode, it can be driven by the signals supplied to the wiring G1 and the wiring S1 and displayed by the optical modulation of the liquid crystal element 340 . When the display is performed in the transmissive mode, the light-emitting element 360 can be driven by the signals supplied to the wiring G2 and the wiring S2 to emit light for display. When the two modes are performed simultaneously, it is possible to drive with the signals supplied to the wiring G1 , the wiring G2 , the wiring S1 , and the wiring S2 .

Although FIG. 9 shows an example in which one liquid crystal element 340 and one light emitting element 360 are provided in one pixel 410, one embodiment of the present invention is not limited thereto. FIG. 10A shows an example in which one liquid crystal element 340 and four light-emitting elements 360 (light-emitting elements 360r, 360g, 360b, and 360w) are provided in one pixel 410 . Unlike FIG. 9 , the pixel 410 shown in FIG. 10A can perform full-color display with one pixel.

In addition to the example of FIG. 9, the pixel 410 in FIG. 10A is connected to the wiring G3 and the wiring S3.

In the example shown in FIG. 10A , for example, as the four light-emitting elements 360 , light-emitting elements exhibiting red (R), green (G), blue (B), and white (W), respectively, can be used. In addition, as the liquid crystal element 340, a reflection type liquid crystal element that emits white light can be used. Thereby, when displaying in the reflection mode, white display with high reflectivity can be performed. When displaying in transmissive mode, high color rendering can be performed with low power consumption.

FIG. 10B shows a structural example of the pixel 410 . The pixel 410 includes a light-emitting element 360w overlapping the opening in the electrode 311 , a light-emitting element 360r arranged around the electrode 311 , a light-emitting element 360g , and a light-emitting element 360b . The light-emitting element 360r, the light-emitting element 360g, and the light-emitting element 360b preferably have almost the same light-emitting area.

<Structure Example 4 of Display Device>

FIG. 11 is a schematic perspective view of a display device 300 according to an embodiment of the present invention. In the display device 300, the substrate 351 and the substrate 361 are bonded together. In FIG. 11, the substrate 361 is represented by a dotted line.

The display device 300 includes a display portion 362, a circuit portion 364, a wiring 365, a circuit portion 366, a wiring 367, and the like. The substrate 351 is provided with, for example, a circuit portion 364, a wiring 365, a circuit portion 366, a wiring 367, an electrode 311b used as a pixel electrode, and the like. In FIG. 11 , IC373 , FPC372 , IC375 , and FPC374 are mounted on substrate 351 . Therefore, the structure shown in FIG. 11 can also be called a display module including the display device 300 , IC373 , FPC372 , IC375 , and FPC374 .

As the circuit section 364, for example, a circuit used as a scanning line driver circuit can be used.

The wiring 365 has a function of supplying signals and power to the display unit and the circuit unit 364 . The signal and power are input to the wiring 365 from the outside via the FPC 372 or from the IC 373 .

FIG. 11 shows an example in which the IC 373 is provided on the substrate 351 by a chip-on-glass (COG) method or the like. As the IC 373, for example, an IC having functions such as a scanning line driver circuit or a signal line driver circuit can be used. Note that when the display device 300 has a circuit serving as a scan line driver circuit or a signal line driver circuit, and when a circuit serving as a scan line driver circuit or a signal line driver circuit is provided externally and is input through the FPC372 to drive the display device When the signal of 300 is used, IC373 may not be set. In addition, IC373 can also be mounted on FPC372 by a chip-on-film (COF) method or the like.

FIG. 12 shows an enlarged view of a part of the display unit 362 . In the display portion 362, electrodes 311b included in a plurality of display elements are arranged in a matrix. The electrode 311b has a function of reflecting visible light and is used as a reflective electrode of the liquid crystal element 340 described below.

As shown in FIG. 12, the electrode 311b has an opening. The light emitting element 360 is provided on the side closer to the substrate 351 than the electrode 311b. Light emitted from the light emitting element 360 is emitted to the substrate 361 side through the opening of the electrode 311b.

FIG. 12 shows a part of the area including the FPC 372 , the part of the area including the circuit part 364 , the part of the area including the display part 362 , the part of the area including the circuit part 366 , and the part including the FPC 374 in the display device shown in FIG. 11 . An example of a section of a portion of a region.

The display device shown in FIG. 12 has a structure in which a display panel 700 and a display panel 800 are stacked. The display panel 700 includes a resin layer 701 and a resin layer 702 . The display panel 800 includes a resin layer 201 and a resin layer 202 . The resin layer 702 and the resin layer 201 are bonded by the adhesive layer 50 . The resin layer 701 is adhered to the substrate 351 by the adhesive layer 51 . The resin layer 202 is adhered to the substrate 361 by the adhesive layer 52 .

[Display panel 700]

The display panel 700 includes a resin layer 701, an insulating layer 478, a plurality of transistors, a capacitor 405, an insulating layer 411, an insulating layer 412, an insulating layer 413, an insulating layer 414, an insulating layer 415, a light-emitting element 360, a spacer 416, an adhesive layer 417 , the colored layer 425 , the light shielding layer 426 , the insulating layer 476 and the resin layer 702 .

The circuit section 364 includes the transistor 401 . The display unit 362 includes a transistor 402 and a transistor 403 .

Each transistor includes a gate electrode, an insulating layer 411 , a semiconductor layer, a source electrode and a drain electrode. The gate electrode and the semiconductor layer overlap each other with the insulating layer 411 interposed therebetween. A part of the insulating layer 411 is used as a gate insulating layer, and the other part of the insulating layer 411 is used as a dielectric of the capacitor 405 . The conductive layer used as the source or drain of transistor 402 is also used as one electrode of capacitor 405 .

The transistor shown in FIG. 12 has a bottom gate structure. In the circuit portion 364 and the display portion 362, the transistor structures may also be different from each other. The circuit unit 364 and the display unit 362 may each include various types of transistors.

Capacitor 405 includes a pair of electrodes and a dielectric therebetween. The capacitor 405 includes a conductive layer formed using the same material and the same process as the gate electrode of the transistor, and a conductive layer formed using the same material and the same process as the source and drain electrodes of the transistor.

The insulating layer 412, the insulating layer 413, and the insulating layer 414 are provided so as to cover the transistors and the like, respectively. The number of insulating layers covering transistors and the like is not particularly limited. The insulating layer 414 is used as a planarization layer. Preferably, at least one of the insulating layer 412 , the insulating layer 413 , and the insulating layer 414 is formed of a material in which impurities such as water and hydrogen are not easily diffused. The diffusion of impurities from the outside into the transistor can be effectively suppressed, so that the reliability of the display device can be improved.

When an organic material is used as the insulating layer 414 , impurities such as moisture may enter the light-emitting element 360 or the like from the outside of the display device through the insulating layer 414 exposed at the end of the display device. Deterioration of the light emitting element 360 due to intrusion of impurities causes deterioration of the display device. Therefore, as shown in FIG. 12, the insulating layer 414 is preferably not located at the end of the display device. In the structure of FIG. 12 , since the insulating layer formed using the organic material is not located at the end of the display device, intrusion of impurities into the light-emitting element 360 can be suppressed.

The light-emitting element 360 includes an electrode 421 , an EL layer 422 and an electrode 423 . Light emitting element 360 may also include optical adjustment layer 424 . The light emitting element 360 has a top emission structure that emits light toward the coloring layer 425 side.

The aperture ratio of the display portion 362 can be increased by arranging transistors, capacitors, wirings, and the like so as to overlap with the light-emitting region of the light-emitting element 360 .

One of the electrode 421 and the electrode 423 is used as an anode, and the other is used as a cathode. When a voltage higher than the threshold voltage of the light emitting element 360 is applied between the counter electrode 421 and the electrode 423, holes are injected into the EL layer 422 from the anode side and electrons are injected from the cathode side. The injected electrons and holes are recombined in the EL layer 422, and the light-emitting substance contained in the EL layer 422 emits light.

Electrode 421 is electrically connected to the source or drain of transistor 403 either directly or through a conductive layer. The electrode 421 is used as a pixel electrode and is provided in each light emitting element 360 . The two adjacent electrodes 421 are electrically insulated by the insulating layer 415 .

The electrode 423 used as a common electrode is commonly used by the plurality of light emitting elements 360 . The electrode 423 is supplied with a constant potential.

The light-emitting element 360 overlaps with the colored layer 425 via the adhesive layer 417 . The spacer 416 overlaps with the light shielding layer 426 via the adhesive layer 417 . Although FIG. 12 shows a case where there is a gap between the electrode 423 and the light shielding layer 426, the electrode 423 and the light shielding layer 426 may be in contact with each other. Although the spacer 416 is provided on the side of the substrate 351 in the structure shown in FIG. 12 , the spacer 416 may also be provided on the side of the substrate 361 (eg, a side closer to the substrate 361 than the light shielding layer 426 ) .

By using a combination of a color filter (colored layer 425 ) and a microcavity structure (optical adjustment layer 424 ), light with high color purity can be extracted from the display device. The thickness of the optical adjustment layer 424 is changed according to the color of each pixel.

The colored layer 425 is a colored layer that transmits light in a specific wavelength region. For example, a color filter that transmits light in a wavelength range of red, green, blue, or yellow can be used.

Note that an embodiment of the present invention is not limited to the color filter method, and an independent color rendering method, a color conversion method, a quantum dot method, and the like may also be used.

The light shielding layer 426 is provided between the adjacent colored layers 425 . The light shielding layer 426 shields the light emitted by the adjacent light emitting elements 360 , thereby suppressing color mixing between the adjacent light emitting elements 360 . Here, by providing the colored layer 425 so that the end portion thereof overlaps with the light shielding layer 426, light leakage can be suppressed. As the light shielding layer 426, a material that shields the light emitted by the light emitting element 360 can be used. Note that by providing the light shielding layer 426 in a region other than the display portion 362 such as the circuit portion 364, unintended light leakage due to waveguide light or the like can be suppressed, which is preferable.

An insulating layer 478 is formed on one surface of the resin layer 701 . An insulating layer 476 is formed on one surface of the resin layer 702 . As the insulating layer 476 and the insulating layer 478, films with high moisture resistance are preferably used. By arranging the light-emitting element 360, the transistor, and the like between a pair of insulating layers having high moisture resistance, it is possible to prevent impurities such as water from entering these elements, thereby improving the reliability of the display device, which is preferable.

Examples of insulating films with high moisture resistance include films containing nitrogen and silicon (for example, silicon nitride films and silicon oxynitride films) and films containing nitrogen and aluminum (for example, aluminum nitride films). In addition, a silicon oxide film, a silicon oxynitride film, an aluminum oxide film, or the like can also be used.

For example, the water vapor transmission rate of the insulating film with high moisture resistance is 1×10 ^-5 [g/(m ² ·day)] or less, preferably 1×10 ^-6 [g/(m ² ·day)] or less , more preferably 1×10 ⁻⁷ [g/(m ² ·day)] or less, and still more preferably 1×10 ⁻⁸ [g/(m ² ·day)] or less.

The connection portion 406 includes the wiring 365 . The wiring 365 can be formed using the same material and the same process as the source and drain of the transistor. The connection portion 406 is electrically connected to an external input terminal that transmits a signal and potential from the outside to the circuit portion 364 . An example in which the FPC372 is provided as an external input terminal is shown here. The FPC 372 and the connection portion 406 are electrically connected through the connection layer 419 .

The connection layer 419 can be formed using various anisotropic conductive films (ACF), anisotropic conductive pastes (ACP), and the like.

The above is the description of the display panel 700 .

[Display panel 800]

The display panel 800 is a reflective liquid crystal display device using a vertical electric field method.

The display panel 800 includes a resin layer 201, an insulating layer 578, a plurality of transistors, a capacitor 505, a wiring 367, an insulating layer 511, an insulating layer 512, an insulating layer 513, an insulating layer 514, a liquid crystal element 529, an alignment film 564a, an alignment film 564b, The adhesive layer 517 , the insulating layer 576 and the resin layer 202 .

The resin layer 201 and the resin layer 202 are bonded together by the adhesive layer 517 . The liquid crystal 563 is sealed in a region surrounded by the resin layer 201 , the resin layer 202 and the adhesive layer 517 . The polarizer 599 is located on the outer side of the substrate 361 .

The liquid crystal element 529 includes the electrode 311 b , the electrode 562 , and the liquid crystal 563 . The electrode 311b is used as a pixel electrode. Electrode 562 is used as a common electrode. By utilizing the electric field generated between the electrode 311b and the electrode 562, the orientation of the liquid crystal 563 can be controlled. An alignment film 564a is provided between the liquid crystal 563 and the electrode 311b. An alignment film 564b is provided between the liquid crystal 563 and the electrode 562 .

On the resin layer 202, an insulating layer 576, an electrode 562, an alignment film 564b, and the like are provided.

On the resin layer 201, the electrode 311b, the alignment film 564a, the transistor 501, the transistor 503, the capacitor 505, the connection part 506, the wiring 367, and the like are provided.

On the resin layer 201, insulating layers such as an insulating layer 511, an insulating layer 512, an insulating layer 513, and an insulating layer 514 are provided.

Note that a part of the conductive layer that is not electrically connected to the electrode 311b, which is used as the source or drain of the transistor 503, may also be used as a part of the signal line. The conductive layer used as the gate of the transistor 503 can also be used as part of the scan line.

FIG. 12 shows an example of the circuit section 366 provided with the transistor 501 .

At least one of the insulating layer 512 and the insulating layer 513 covering each transistor is preferably made of a material that does not easily diffuse impurities such as water and hydrogen.

An electrode 311b is provided on the insulating layer 514 . The electrode 311b is electrically connected to one of the source and drain of the transistor 503 through openings formed in the insulating layer 514, the insulating layer 513, the insulating layer 512, and the like. The electrode 311b is electrically connected to one electrode of the capacitor 505 .

Since the display panel 800 is a reflective liquid crystal display device, a conductive material that reflects visible light is used for the electrode 311 b, and a conductive material that transmits visible light is used for the electrode 562 .

As the conductive material that transmits visible light, for example, a material containing one selected from the group consisting of indium (In), zinc (Zn), and tin (Sn) is preferably used. Specifically, indium oxide, indium tin oxide (ITO), indium zinc oxide, indium oxide containing tungsten oxide, indium zinc oxide containing tungsten oxide, indium oxide containing titanium oxide, indium oxide containing Indium tin oxide of titanium, indium tin oxide (ITSO) containing silicon oxide, zinc oxide, zinc oxide containing gallium, and the like. Note that a graphene-containing film may also be used. The graphene-containing film can be formed, for example, by reducing the graphene oxide-containing film.

Examples of conductive materials that reflect visible light include aluminum, silver, or alloys containing any of these metal materials, and the like. In addition, metal materials such as gold, platinum, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, or palladium, or an alloy containing any of these metal materials can be used. In addition, lanthanum, neodymium, germanium, or the like may be added to the above-mentioned metal material or alloy. In addition, alloys containing aluminum (aluminum alloys) such as alloys of aluminum and titanium, alloys of aluminum and nickel, alloys of aluminum and neodymium, alloys of aluminum, nickel, and lanthanum (Al-Ni-La), and silver and copper can also be used. alloys of silver, palladium and copper (Ag-Pd-Cu, also referred to as APC) or alloys of silver and magnesium, and other alloys containing silver.

As the polarizer 599, a linear polarizer or a circular polarizer may be used. As the circular polarizer, for example, a stack including a linear polarizer and a quarter-wave retardation plate can be used. This structure can suppress reflection of external light. A desired contrast ratio is achieved by adjusting the cell gap, orientation, driving voltage, etc. of the liquid crystal element used for the liquid crystal element 529 according to the type of the polarizer 599 .

The electrode 562 is electrically connected to the conductive layer provided on the resin layer 201 side through the connecting body 543 in the vicinity of the end portion of the resin layer 202 . Thereby, a potential or a signal can be supplied to the electrode 562 from the FPC 374 or the IC or the like arranged on the resin layer 201 side.

As the connecting body 543, for example, conductive particles can be used. As the conductive particles, particles of an organic resin, silica, or the like whose surfaces are covered with a metal material can be used. As the metal material, nickel or gold is preferably used because it can reduce contact resistance. In addition, it is preferable to use particles in which two or more kinds of metal materials are coated in layers, such as gold and the like on nickel. As the connecting body 543, a material capable of elastic deformation or plastic deformation is preferably used. At this time, the connecting body 543 of the conductive particles may have a shape that is crushed in the longitudinal direction as shown in FIG. 12 . By having the crushed shape, the contact area between the connecting body 543 and the conductive layer electrically connected to the connecting body 543 can be increased, so that the contact resistance can be reduced and the occurrence of problems such as poor contact can be suppressed.

The connecting body 543 is preferably arranged so as to be covered with the adhesive layer 517 . For example, the connectors 543 may be pre-dispersed in the adhesive layer 517 before being cured.

A connection portion 506 is provided in a region near the end portion of the resin layer 201 . The connection portion 506 is electrically connected to the FPC 374 through the connection layer 519 .

This concludes the description of the display panel 800 .

[display element]

As the display element included in the first pixel on the display surface side, an element that reflects external light for display can be used. Because such an element does not include a light source, power consumption during display can be made extremely small. As the display element included in the first pixel, a reflective liquid crystal element can be typically used. Alternatively, as the display element included in the first pixel, not only a shutter-type microelectromechanical system (MEMS) element, an optical interference-type MEMS element, but also an applied microcapsule method, an electrophoresis method, and an electrowetting method can be used. , electronic powder fluid (registered trademark) method, etc.

As the display element included in the second pixel on the opposite side to the display surface, an element including a light source and performing display using light from the light source can be used. Since the brightness and chromaticity of light emitted by such pixels are not affected by external light, such pixels can perform display with high color reproducibility (wide color gamut) and high contrast, that is, clear display. As the display element included in the second pixel, for example, a self-luminous light-emitting element such as an organic light-emitting diode (OLED), a light-emitting diode (LED), and a quantum dot light-emitting diode (QLED) can be used. Alternatively, as the display element included in the second pixel, a backlight that is a light source and a transmissive liquid crystal element that controls the transmittance of light from the backlight may be used in combination.

[liquid crystal element]

As the liquid crystal element, an element using a vertical alignment (VA) mode can be used. As the vertical alignment mode, a multi-quadrant vertical alignment (MVA) mode, a vertical alignment configuration (PVA) mode, an advanced hypervision (ASV) mode, or the like can be used.

As the liquid crystal element, various modes can be employed. For example, twisted nematic (TN) mode, in-plane switching (IPS) mode, fringing field switching (FFS) mode; axis-symmetrically aligned microcell (ASM) mode, optically compensated bending (OCB) mode, ferroelectric liquid crystal can be used (FLC) mode, antiferroelectric liquid crystal (AFLC) mode, etc. replace the liquid crystal element of the VA mode.

The liquid crystal element controls the transmission or non-transmission of light by utilizing the optical modulation effect of liquid crystal. The optical modulation of the liquid crystal is controlled by an electric field (including a transverse electric field, a longitudinal electric field or an electric field in an oblique direction) applied to the liquid crystal. As the liquid crystal used for the liquid crystal element, thermotropic liquid crystal, low molecular liquid crystal, polymer liquid crystal, polymer dispersed liquid crystal (PDLC), ferroelectric liquid crystal, antiferroelectric liquid crystal, guest-host liquid crystal, or the like can be used. These liquid crystal materials exhibit a cholesteric phase, a smectic phase, a cubic phase, a chiral nematic phase, and an isotropic phase depending on conditions.

As the liquid crystal material, either positive type liquid crystal or negative type liquid crystal can be used, and an appropriate liquid crystal material can be adopted according to the applied mode or design.

In order to control the alignment of the liquid crystal, an alignment film may be provided. When the transverse electric field method is employed, a liquid crystal exhibiting a blue phase without using an alignment film may be used. The blue phase is a type of liquid crystal phase, and refers to a phase that appears just before the transition from the cholesteric phase to the homogeneous phase when the temperature of the cholesteric liquid crystal is raised. Since the blue phase appears only in a narrow temperature range, a liquid crystal composition in which a chiral agent of several wt % or more is mixed is used for the liquid crystal layer to widen the temperature range. A liquid crystal composition containing a liquid crystal exhibiting a blue phase and a chiral agent has a high response speed and is optically isotropic. In addition, a liquid crystal composition containing a liquid crystal exhibiting a blue phase and a chiral agent does not require alignment treatment and has little viewing angle dependence. Since there is no need to provide an alignment film and no rubbing treatment is required, electrostatic breakdown due to the rubbing treatment can be prevented, and defects and breakage of the liquid crystal display device in the manufacturing process can be reduced.

When a reflective liquid crystal element is used, the polarizing plate is provided on the display surface side. Moreover, when a light-diffusion plate is provided separately on the display surface side, since visibility can be improved, it is preferable.

[Light-emitting element]

As the light-emitting element, an element capable of self-luminescence can be used, and an element whose luminance is controlled by current or voltage is included in the category of the light-emitting element. For example, LEDs, QLEDs, organic EL elements, or inorganic EL elements can be used, but any of the light-emitting elements described in Embodiments 1 and 2 is preferably used.

In this embodiment mode, in particular, the light-emitting element preferably has a top emission structure. A conductive film that transmits visible light is used as the electrode on the light-extracting side. It is preferable to use a conductive film reflecting visible light as the electrode on the side where light is not extracted. The light-emitting element may be a single element including one EL layer or a tandem element in which a plurality of EL layers are stacked with a charge generating layer interposed therebetween.

The EL layer includes at least a light-emitting layer. In addition to the light-emitting layer, the EL layer may further include a substance containing a high hole injecting property, a substance having a high hole transport property, a hole blocking material, a substance having a high electron transport property, a substance having a high electron injecting property, or a bipolar substance (substance with high electron-transporting properties and hole-transporting properties) or the like is one layer or a plurality of layers.

As the EL layer, the low molecular weight compounds, high molecular weight compounds, and inorganic compounds mentioned in Embodiment 1 can be used. The layers included in the EL layer can be formed by any of the following methods: evaporation method (including vacuum evaporation method), transfer method, printing method, inkjet method, coating method, and the like, respectively.

[Adhesive Layer]

As the adhesive layer, various curing adhesives such as photocurable adhesives such as ultraviolet curing adhesives, reaction curing adhesives, thermosetting adhesives, and anaerobic adhesives can be used. Examples of these adhesives include epoxy resins, acrylic resins, silicone resins, phenolic resins, polyimide resins, imide resins, polyvinyl chloride (PVC) resins, polyvinyl butyral (PVB) resins. ) resin, ethylene-vinyl acetate (EVA) resin, etc. In particular, materials with low moisture permeability such as epoxy resins are preferably used. In addition, a two-liquid mixed type resin can also be used. In addition, an adhesive sheet or the like can also be used.

In addition, a drying agent may be contained in the said resin. For example, a substance that adsorbs moisture by chemical adsorption, such as an oxide of an alkaline earth metal (calcium oxide, barium oxide, etc.), can be used. Alternatively, a substance that adsorbs moisture by physical adsorption, such as zeolite or silica gel, may be used. When the desiccant is contained in the resin, it is possible to suppress the entry of impurities such as moisture into the element, thereby improving the reliability of the display panel, which is preferable.

In addition, the light extraction efficiency can be improved by mixing a filler with a high refractive index or a light scattering member in the above-mentioned resin. For example, titanium oxide, barium oxide, zeolite, zirconium and the like can be used.

[connection layer]

As the connection layer, an anisotropic conductive film (ACF), an anisotropic conductive paste (ACP), or the like can be used.

[coloring layer]

As a material which can be used for a colored layer, a metal material, a resin material, a resin material containing a pigment or a dye, etc. are mentioned.

[shading layer]

Examples of materials that can be used for the light-shielding layer include carbon black, titanium black, metals, metal oxides, and composite oxides containing solid solutions of a plurality of metal oxides. The light shielding layer may be a film containing a resin material or a thin film containing an inorganic material such as a metal. Moreover, you may use the laminated|multilayer film of the film containing the material of a coloring layer for a light-shielding layer. For example, a laminated structure of a film containing a material for a colored layer for transmitting light of a certain color and a film containing a material for a coloring layer for transmitting light of another color can be employed. By making the material of the colored layer and the light-shielding layer the same, in addition to using the same equipment, it is possible to simplify the process, which is preferable.

The structure shown in this embodiment mode can be appropriately combined with any structure shown in other embodiment modes.

(Embodiment 5)

In this embodiment mode, electronic devices each including the light-emitting elements shown in Embodiment Mode 1 and Embodiment Mode 2 will be described. Since the light-emitting elements described in Embodiments 1 and 2 have the light-emitting element according to one embodiment of the present invention, they have high luminous efficiency and high reliability. As a result, the electronic devices described in this embodiment can each include power consumption. A display portion with reduced volume and high reliability.

<Display Module>

In the display module 6000 shown in FIG. 13A , a display panel 6006 connected to the FPC 6005 , a frame 6009 , a printed circuit board 6010 and a battery 6011 are provided between the upper cover 6001 and the lower cover 6002 .

For example, the above-described display device manufactured using one embodiment of the present invention can be used for the display panel 6006 . Thereby, the display module can be manufactured with high yield.

The shape and size of the upper cover 6001 and the lower cover 6002 can be appropriately changed according to the size of the display panel 6006 .

In addition, a touch panel may be provided so as to overlap with the display panel 6006 . The touch panel may be a resistive film type touch panel or an electrostatic capacitance type touch panel, and can be formed to overlap with the display panel 6006 . In addition, instead of providing a touch panel, the display panel 6006 may have a touch panel function.

The frame 6009 protects the display panel 6006 and is used as an electromagnetic shield to block electromagnetic waves generated by the operation of the printed circuit board 6010 . The frame 6009 can also be used as a heat sink.

The printed circuit board 6010 includes power supply circuits and signal processing circuits for outputting video signals and clock signals. As a power supply for supplying power to the power supply circuit, an external commercial power supply or a separately provided battery 6011 can be used. When a commercial power source is used, the battery 6011 can be omitted.

The display module 6000 may also be provided with components such as polarizers, retardation plates, prism sheets, and the like.

13B is a schematic cross-sectional view of a display module 6000 including an optical touch sensor.

The display module 6000 includes a light-emitting portion 6015 and a light-receiving portion 6016 provided on the printed circuit board 6010 . A pair of light guide parts (light guide part 6017a, light guide part 6017b) are provided in an area surrounded by the upper cover 6001 and the lower cover 6002.

For the upper cover 6001 and the lower cover 6002, for example, plastic or the like can be used. The upper cover 6001 and the lower cover 6002 may be respectively thin (eg, 0.5 mm or more and 5 mm or less). At this time, the weight of the display module 6000 can be made extremely light. In addition, since the upper cover 6001 and the lower cover 6002 can be manufactured with less material, the manufacturing cost can be reduced.

The display panel 6006 is overlapped with the printed circuit board 6010 and the battery 6011 via the frame 6009 . The display panel 6006 and the frame 6009 are fixed to the light guide portion 6017a and the light guide portion 6017b.

The light 6018 emitted from the light emitting portion 6015 passes through the upper portion of the display panel 6006 through the light guide portion 6017a, and reaches the light receiving portion 6016 through the light guide portion 6017b. For example, when the light 6018 is blocked by a detection object such as a finger or a stylus, it can be detected as a touch operation.

The plurality of light emitting parts 6015 are provided along, for example, two adjacent sides of the display panel 6006 . The plurality of light receiving units 6016 are arranged so as to face the light emitting unit 6015 with the display panel 6006 therebetween. Thereby, information on the position of the touch operation can be acquired.

As the light-emitting portion 6015, a light source such as an LED element can be used, for example. In particular, as the light-emitting portion 6015, it is preferable to use a light source that emits infrared rays which are not visible to the user and are harmless to the user.

As the light-receiving portion 6016, a photoelectric element that receives the light emitted by the light-emitting portion 6015 and converts it into an electrical signal can be used. It is preferable to use a photodiode capable of receiving infrared rays.

As the light guide portion 6017a and the light guide portion 6017b, a member that transmits at least the light 6018 can be used. By using the light guide portion 6017a and the light guide portion 6017b, the light-emitting portion 6015 and the light-receiving portion 6016 can be arranged below the display panel 6006, thereby preventing external light from reaching the light-receiving portion 6016 and causing malfunction of the touch sensor. In particular, it is preferable to use a resin that absorbs visible light and transmits infrared rays. Thereby, erroneous operation of the touch sensor is more effectively suppressed.

One embodiment of the present invention can be used for at least the display panel 6006 .

<Electronic Equipment>

14A-14G illustrate an electronic device. These electronic devices may include a casing 9000, a display portion 9001, a speaker 9003, operation keys 9005 (including a power switch or an operation switch), connection terminals 9006, and sensors 9007 (sensors that measure or detect the following factors: force, displacement, Position, Velocity, Acceleration, Angular Velocity, Rotational Speed, Distance, Light, Liquid, Magnetic, Temperature, Chemical, Sound, Time, Hardness, Electric Field, Current, Voltage, Electricity, Radiation, Flow, Humidity, Inclination, Vibration, Smell or infrared), microphone 9008, etc. In addition, the sensor 9007 may have a function of measuring biological information, such as a pulse sensor and a fingerprint sensor.

The electronic devices shown in FIGS. 14A to 14G may have various functions. The electronic device shown in FIGS. 14A to 14G may have, for example, the following functions: a function of displaying various data (still images, moving images, text images, etc.) on a display unit; a touch sensor function; a calendar, date, and time display function of controlling processing by using various software (programs); wireless communication function; function of connecting to various computer networks by using wireless communication function; transmission and reception of various data by using wireless communication function function; the function of reading out the program or data stored in the storage medium to display the program or data on the display unit; etc. Note that the functions that the electronic device shown in FIGS. 14A to 14G can have are not limited to the above-described functions, but the electronic device can have various functions. Although not illustrated in FIGS. 14A to 14G , the electronic device may include a plurality of display parts. The electronic device may also have a camera or the like and the following functions: a function of capturing a still image; a function of capturing a moving image; a function of storing the captured image in a storage medium (an external storage medium or a storage medium built into the camera); The function of displaying the captured image on the display section; etc.

Next, the electronic apparatus shown in FIGS. 14A to 14G will be described in detail.

FIG. 14A is a perspective view of the portable information terminal 9100 . The display portion 9001 of the portable information terminal 9100 has flexibility. Therefore, the display part 9001 can be assembled along the curved surface of the curved frame body 9000 . In addition, the display unit 9001 is provided with a touch sensor, and can be operated by touching the screen with a finger, a stylus pen, or the like. For example, by touching an icon displayed on the display unit 9001, an application can be activated.

14B is a perspective view of the portable information terminal 9101. The portable information terminal 9101 has, for example, one or more functions of a telephone, an electronic notebook, and an information reading system. Specifically, the portable information terminal can be used as a smartphone. Note that a speaker 9003, a connection terminal 9006, a sensor 9007, and the like not shown in FIG. 14B may be located in the portable information terminal 9101 like the portable information terminal 9100 shown in FIG. 14A. The portable information terminal 9101 can display text and image information on its multiple faces. For example, three operation buttons 9050 (also called operation icons or just icons) may be displayed on one surface of the display portion 9001 . In addition, information 9051 represented by a dotted rectangle can be displayed on the other surface of the display unit 9001 . Examples of the information 9051 include displays indicating receipt of e-mail, social network service (SNS) messages, and telephone calls, etc.; titles and sender names of e-mails and SNS messages; date; time; battery remaining; Display of reception strength, etc. Instead of the information 9051, an operation button 9050 or the like may be displayed at the position where the information 9051 is displayed.

As the material of the housing 9000, for example, alloys, plastics, ceramics, or the like can be used. As plastic, reinforced plastic can also be used. Carbon fiber reinforced composite (CFRP), one of the reinforced plastics, has the advantages of being lightweight and non-corrosive. Other examples of reinforced plastics include reinforced plastics including glass fibers and reinforced plastics including aramid fibers. Alloys are preferred because the fibers are more likely to peel from the resin when subjected to a strong impact than alloys. Examples of the alloy include aluminum alloys and magnesium alloys. Amorphous alloys (also called metallic glasses) containing zirconium, copper, nickel, titanium, in particular, have high elastic strength. The amorphous alloy has a glass transition region at room temperature, also known as a bulk solidified amorphous alloy, and has an essentially amorphous atomic structure. By using the solidification casting method, the alloy material is cast into a mold of at least a part of the frame body and solidified, and a part of the frame body is formed by solidifying the amorphous alloy using a bulk. The amorphous alloy may contain beryllium, silicon, niobium, boron, gallium, molybdenum, tungsten, manganese, iron, cobalt, yttrium, vanadium, phosphorus, carbon, and the like in addition to zirconium, copper, nickel, and titanium. Amorphous alloys may be formed by vacuum deposition, sputtering, electroplating, electroless plating, etc. instead of solidification casting. The amorphous alloy may contain microcrystals or nanocrystals as long as it maintains a state without long-range order (periodic structure) as a whole. Note that the term alloy refers to both a complete solid solution alloy having a single solid phase structure and a partial solution having two or more phases. The frame body 9000 using an amorphous alloy can have high elastic strength. By including an amorphous alloy in the housing 9000, even if the portable information terminal 9101 is dropped and temporarily deformed by an impact, the portable information terminal 9101 can be restored to its original shape, so that the impact resistance of the portable information terminal 9101 can be improved.

14C is a perspective view of the portable information terminal 9102. The portable information terminal 9102 has a function of displaying information on three or more surfaces of the display unit 9001 . Here, information 9052, information 9053, and information 9054 are displayed on different surfaces. For example, the user of the portable information terminal 9102 can confirm its display (here, information 9053) in a state where the portable information terminal 9102 is put in his/her pocket. Specifically, the telephone number, name, etc. of the person making the call are displayed at a position that can be viewed from above the portable information terminal 9102 . Therefore, the user can confirm the display without taking the portable information terminal 9102 out of his pocket, and can judge whether to answer the phone.

FIG. 14D is a perspective view of the wristwatch-type portable information terminal 9200 . The portable information terminal 9200 can execute various application programs such as mobile phone, e-mail, reading and editing of articles, music playback, network communication, and computer games. The display surface of the display unit 9001 is curved, and images can be displayed on the curved display surface. The portable information terminal 9200 can employ near field communication as a communication method based on an existing communication standard. In this case, for example, mutual communication between the portable information terminal and a headset capable of wireless communication can be performed, whereby hands-free calling can be performed. The portable information terminal 9200 includes a connection terminal 9006, and can directly transmit and receive data with other information terminals through the connector. Charging can be performed through the connection terminal 9006 . In addition, the charging operation can also be performed using wireless power supply without using the connection terminal 9006 .

14E , 14F and 14G are perspective views of the foldable portable information terminal 9201 . FIG. 14E is a perspective view showing the portable information terminal 9201 unfolded. FIG. 14F is a perspective view showing the portable information terminal 9201 in the middle of unfolding or folding. FIG. 14G is a perspective view showing the portable information terminal 9201 folded. The portable information terminal 9201 is highly portable when folded, and when the portable information terminal 9201 is unfolded, a large display area that is seamlessly spliced can be easily seen at a glance. The display portion 9001 of the portable information terminal 9201 is supported by three housings 9000 connected together by hinges 9055 . By bending the portable information terminal 9201 at the connecting portion between the two housings 9000 by the hinge 9055, the shape of the portable information terminal 9201 can be reversibly changed from the unfolded state to the folded state. For example, the portable information terminal 9201 may be curved with a curvature radius of 1 mm or more and 150 mm or less.

Examples of electronic equipment are: television sets (also called televisions or television receivers); display screens of computers, etc.; cameras such as digital cameras or digital video cameras; digital photo frames; mobile phones (also called mobile phones, mobile telephone sets) Goggle-type display devices (wearable displays); portable game machines; portable information terminals; sound reproduction devices; large game machines such as pachinko machines.

In addition, the electronic device of one embodiment of the present invention may include a secondary battery. It is preferable to be able to charge the secondary battery by non-contact power transmission.

Examples of secondary batteries include lithium ion secondary batteries such as lithium polymer batteries (lithium ion polymer batteries) using gel electrolytes, lithium ion batteries, nickel metal hydride batteries, nickel cadmium batteries, organic radical batteries, lead storage batteries, air Secondary batteries, nickel-zinc batteries, silver-zinc batteries, etc.

The electronic device of one embodiment of the present invention may also include an antenna. By receiving signals through the antenna, images, data, and the like can be displayed on the display unit. When the electronic device includes a secondary battery, the antenna can be used for non-contact power transmission.

15A-15C illustrate a foldable electronic device.

The electronic device 900 shown in FIG. 15A includes a housing 901a, a housing 901b, a hinge 903, a display portion 902, and the like. The display unit 902 is mounted in the casings 901a and 901b.

The frame body 901a and the frame body 901b are rotatably connected by a hinge 903 . The electronic device 900 can be deformed into a state in which the frame body 901a and the frame body 901b are closed and a state in which they are opened as shown in FIG. 15A . Thereby, the portability of the electronic device when being carried is good, and since it has a large display area, the visibility when it is used is high.

In order to prevent the angle formed by the frame body 901a and the frame body 901b from exceeding a predetermined angle when the frame body 901a and the frame body 901b are opened, the hinge 903 preferably has a locking mechanism. For example, the locking angle (no further opening) is preferably more than 90° and less than 180°, and typically, it can be 90°, 120°, 135°, 150° or 175°, etc. Thereby, convenience, safety, and reliability can be improved.

The display unit 902 is used as a touch panel, and can be operated with a finger, a stylus pen, or the like.

One of the housings 901a and 901b is provided with a wireless communication module, and data can be sent and received through a computer network such as the Internet, a local area network (LAN), and Wi-Fi (registered trademark).

The display portion 902 is preferably formed using one flexible display, and in this case, images can be displayed continuously across the frame body 901a and the frame body 901b. Note that each of the frame body 901a and the frame body 901b may be provided with a display.

FIG. 15B shows the electronic device 910 used as a portable game machine. The electronic device 910 includes a casing 911a, a casing 911b, a display portion 912, a hinge 913, an operation button 914a, an operation button 914b, and the like.

The case 915 can be inserted into the frame body 911b. Application software such as a game is stored in the box 915 , and various applications can be executed using the electronic device 910 by exchanging the box 915 .

FIG. 15B shows an example in which the size of the portion of the display portion 912 overlapping the frame body 911 a and the size of the portion of the display portion 912 overlapping the frame body 911 b are different from each other. Specifically, a part of the display part 912 in the casing 911a is larger than a part of the display part 912 overlapping the casing 911b in which the operation buttons 914a and the operation buttons 914b are provided. For example, the display portion can be used for different purposes by displaying the side of the frame body 911a of the display portion 912 as a main screen and the side of the frame body 911b of the display portion 912 as an operation screen.

In the electronic device 920 shown in FIG. 15C , a flexible display portion 922 is provided across the frame body 921 a and the frame body 921 b connected by the hinge 923 .

FIG. 15C shows an embodiment in which the display portion 922 is unfolded with a large curvature when the frame body 921a and the frame body 921b are exposed. For example, the display portion 922 may be held in a state where the radius of curvature is 1 mm or more and 50 mm or less, preferably 5 mm or more and 30 mm or less. A part of the display part 922 is provided with pixels continuously arranged across the frame body 921a and the frame body 921b, so that curved surface display can be performed.

The hinge 923 has the above-described locking mechanism, so that excessive force is not applied to the display portion 922, so that damage to the display portion 922 can be prevented. Thereby, a highly reliable electronic device can be realized.

FIG. 16A shows a video camera including a frame body 7701, a frame body 7702, a display portion 7703, operation keys 7704, a lens 7705, a connection portion 7706, and the like. The operation keys 7704 and the lens 7705 are provided in the housing 7701 , and the display unit 7703 is provided in the housing 7702 . The frame body 7701 and the frame body 7702 are connected to each other by the connecting portion 7706 , and the angle between the frame body 7701 and the frame body 7702 can be changed by the connecting portion 7706 . The image displayed on the display unit 7703 can also be switched according to the angle of the connection portion 7706 between the housing 7701 and the housing 7702 .

16B shows a notebook-type personal computer including a casing 7121, a display unit 7122, a keyboard 7123, a pointing device 7124, and the like. In addition, since the display unit 7122 has high pixel density and high definition, although the display unit 7122 is small and medium-sized, 8k display can be performed, and a very clear image can be obtained.

FIG. 16C is an appearance of the head-mounted display 7200 .

The head-mounted display 7200 includes a mounting portion 7201, a lens 7202, a main body 7203, a display portion 7204, a cable 7205, and the like. Mounting portion 7201 includes battery 7206 .

Power is supplied from the battery 7206 to the main body 7203 through the cable 7205. The main body 7203 is provided with a wireless receiver or the like to receive video data such as image data and display it on the display section 7204 . The camera in the main body 7203 captures the movements of the user's eyeballs and eyelids, and then uses the captured data to calculate the coordinates of the user's viewpoint, using the user's viewpoint as an input unit.

The mounting portion 7201 may include a plurality of electrodes in contact with the user. The main body 7203 may also have a function of recognizing the user's line of sight by detecting the current flowing through the electrodes according to the movement of the user's eyeballs. The main body 7203 may have a function of monitoring the pulse of the user by detecting the current flowing through the electrode. The mounting part 7201 may have sensors such as a temperature sensor, a pressure sensor, an acceleration sensor, and the like, whereby the user's biological information can be displayed on the display part 7204 . The main body 7203 may detect the movement of the user's head or the like and move the image displayed on the display unit 7204 in synchronization with the movement of the user's head or the like.

FIG. 16D is the appearance of the camera 7300 . The camera 7300 includes a housing 7301, a display portion 7302, operation buttons 7303, a shutter button 7304, a connection portion 7305, and the like. A lens 7306 may also be placed on the camera 7300.

The connection portion 7305 includes electrodes to be connected to a viewfinder 7400, a flash device, and the like, which will be described later.

Although the lens 7306 of the camera 7300 can be detached from the housing 7301 and exchanged here, the lens 7306 may be included in the housing 7301.

By pressing the shutter button 7304, an image can be captured. In addition, it is also possible to capture and image by operating the display unit 7302 including a touch sensor.

In the display unit 7302, a display device or a touch sensor according to an embodiment of the present invention can be applied.

FIG. 16E shows the camera 7300 connected to the viewfinder 7400.

The viewfinder 7400 includes a housing 7401, a display unit 7402, a button 7403, and the like.

The housing 7401 includes a connecting portion to be fitted to the connecting portion 7305 of the camera 7300 , so that the viewfinder 7400 can be connected to the camera 7300 . The connection portion includes electrodes, and images and the like received from the camera 7300 through the electrodes can be displayed on the display portion 7402 .

Button 7403 is used as a power button. By using the button 7403, the display/non-display of the display unit 7402 can be switched.

In FIGS. 16D and 16E , the camera 7300 and the viewfinder 7400 are separate and detachable electronic devices, but the housing 7301 of the camera 7300 may include a viewfinder having a display device or a touch sensor according to an embodiment of the present invention.

17A to 17E are external views of the head mounted displays 7500 and 7510 .

The head mounted display 7500 includes a frame body 7501 , two display parts 7502 , operation buttons 7503 , and a fixing strap 7504 .

The head-mounted display 7500 has the functions of the above-described head-mounted display 7200, and further includes two display units.

By including two display parts 7502, the user can see one display part with one eye and the other display part with the other eye. This makes it possible to display a high-resolution image even when performing three-dimensional display using parallax or the like. The display portion 7502 is curved in an arc shape substantially centered on the user's eyes. Therefore, since the distance between the user's eyes and the display surface of the display unit is constant, the user can see a more natural image. Even when the brightness or chromaticity of the light from the display section changes according to the viewing angle of the user, since the user's eyes are located in the normal direction of the display surface of the display section and the influence of the change can be substantially ignored, it is possible to Displays a more realistic image.

The operation button 7503 functions as a power button or the like. In addition, buttons other than the operation button 7503 may also be included.

The head-mounted display 7510 includes a housing 7501 , a display portion 7502 , a fixing band 7504 , and a pair of lenses 7505 .

The user can see the display on the display part 7502 through the lens 7505 . Preferably, the display portion 7502 is curved. By arranging the display portion 7502 in a curved manner, the user can feel the high realism of the image.

The display device of one embodiment of the present invention can be applied to the display unit 7502 . Since the display device according to one embodiment of the present invention can have a high resolution, even if an image is enlarged using the lens 7505 as shown in FIG. 17E , a more realistic image can be displayed without allowing the user to see pixels.

FIG. 18A shows an example of a television apparatus. In the television device 9300 , the display unit 9001 is incorporated in the housing 9000 . Here, the frame body 9000 is supported by the bracket 9301 .

The operation of the television device 9300 shown in FIG. 18A can be performed by using an operation switch of the housing 9000 or a remote control operator 9311. The display unit 9001 may include a touch sensor. The television device 9300 can be operated by touching the display unit 9001 with a finger or the like. The remote control unit 9311 may include a display unit that displays data output from the remote control unit 9311 . By using the operation keys of the remote control unit 9311 or the touch panel, the channel and volume can be controlled, and the image displayed on the display unit 9001 can be controlled.

The television apparatus 9300 includes a receiver, a modem, and the like. General television broadcasts can be received by using a receiver. Furthermore, by connecting the television set to a wired or wireless communication network through a modem, information communication can be performed in one-way (from sender to receiver) or two-way (between sender and receiver or between receivers).

Since the electronic device or lighting device of one embodiment of the present invention is flexible, the electronic device or lighting device can also be assembled along the curved surfaces of the inner/outer walls of houses or tall buildings, and the curved surfaces of interior/exterior decorations of automobiles.

FIG. 18B is the appearance of the automobile 9700. FIG. FIG. 18C shows the driver's seat of automobile 9700 . The automobile 9700 includes a body 9701, wheels 9702, a dashboard 9703, lights 9704, and the like. The display device, the light-emitting device, or the like according to one embodiment of the present invention can be used for a display unit of an automobile 9700 or the like. For example, a display device, a light-emitting device, or the like according to an embodiment of the present invention can be used for the display parts 9710 to 9715 shown in FIG. 18C .

The display unit 9710 and the display unit 9711 are display devices provided in the windshield of the automobile. By using a light-transmitting conductive material for its electrodes and wirings, the display device, the light-emitting device, or the like according to one embodiment of the present invention can be a transparent display device that can see the opposite side. Such a transparent display portion 9710 or transparent display portion 9711 does not obstruct the driver's field of vision when driving the automobile 9700 . Therefore, the display device, the light-emitting device, or the like according to one embodiment of the present invention can be installed in the windshield of the automobile 9700 . In addition, when providing a transistor for driving a display device, a light-emitting device, or the like, it is preferable to use a light-transmitting transistor such as an organic transistor using an organic semiconductor material or a transistor using an oxide semiconductor.

The display portion 9712 is a display device provided in the column portion. For example, by displaying an image captured by an imaging device provided in the vehicle body on the display unit 9712, the field of view partially blocked by the pillar can be supplemented. The display unit 9713 is a display device provided on the instrument panel. For example, by displaying an image captured by an imaging device provided in the vehicle body on the display unit 9713, the field of view blocked by the instrument panel can be supplemented. That is, by displaying the image captured by the imaging means provided outside the vehicle, the blind spot can be supplemented, and the safety can be improved. By displaying an image that complements the portion that the driver cannot see, the driver can be easily and comfortably checked for safety.

FIG. 18D shows an interior of an automobile in which a bench seat is used as the driver's seat and the passenger's seat. The display portion 9721 is a display device provided in the door portion. For example, by displaying an image captured by an imaging device provided in the vehicle body on the display unit 9721, the field of view blocked by the door can be supplemented. The display unit 9722 is a display device provided in the steering wheel. The display unit 9723 is a display device provided in the center of the seating surface of the bench seat. In addition, the display device can also be used as a seat heater by arranging the display device on the seat surface or the backrest portion and using the heat generated by the display device as a heat source.

The display unit 9714, the display unit 9715, and the display unit 9722 can display various information such as navigation data, a speedometer, a tachometer, a mileage, a fuel gauge, a gear indicator, and air conditioner settings. The user can appropriately change the content and layout displayed on the display unit. The display unit 9710 to the display unit 9713, the display unit 9721, and the display unit 9723 can also display the above-mentioned information. The display parts 9710 to 9715, and the display parts 9721 to 9723 can also be used as lighting devices. The display parts 9710 to 9715 and the display parts 9721 to 9723 can also be used as heating means.

The display device 9500 shown in FIGS. 19A and 19B includes a plurality of display panels 9501 , a shaft portion 9511 , and a bearing portion 9512 . Each of the plurality of display panels 9501 includes a display area 9502 and a light-transmitting area 9503 .

Each of the plurality of display panels 9501 has flexibility. Two adjacent display panels 9501 are arranged in such a manner that a part thereof overlaps with each other. For example, the light-transmitting regions 9503 of two adjacent display panels 9501 may overlap each other. By using a plurality of display panels 9501, a display device having a large screen can be obtained. The display panel 9501 can be rolled according to its use, so the versatility of the display device is high.

In addition, in FIGS. 19A and 19B , the display areas 9502 of adjacent display panels 9501 are separated from each other, but this structure is not limited. For example, the display areas 9502 of adjacent display panels 9501 may be overlapped with each other without a gap. , a continuous display area 9502 is obtained.

The electronic device shown in this embodiment includes a display unit for displaying some information. Note that the light-emitting element of one embodiment of the present invention can also be applied to an electronic device that does not include a display portion. Although the display part of the electronic device is flexible and can be displayed on a curved display surface or a structure in which the display part of the electronic device can be folded, the structure is not limited to this, and may be The structure of the display portion of an electronic device that has no flexibility and displays on a flat portion is adopted.

The configuration shown in this embodiment mode can be used in combination with any configuration shown in other embodiments as appropriate.

(Embodiment 6)

In this embodiment mode, a light-emitting device including a light-emitting element according to an embodiment of the present invention will be described with reference to FIGS. 20A to 20C and FIGS. 21A to 21D .

<Light-emitting device>

FIG. 20A is a perspective view of the light-emitting device 3000 according to the present embodiment, and FIG. 20B is a cross-sectional view taken along the chain line E-F shown in FIG. 20A . Note that, in FIG. 20A , in order to avoid complexity, some of the constituent elements are indicated by dotted lines.

The light-emitting device 3000 shown in FIGS. 20A and 20B includes a substrate 3001 , a light-emitting element 3005 on the substrate 3001 , a first sealing region 3007 provided on the outer periphery of the light-emitting element 3005 , and a first sealing region 3007 provided on the outer periphery of the first sealing region 3007 . Two sealing areas 3009.

Light emission from the light emitting element 3005 is emitted from one or both of the substrate 3001 and the substrate 3003 . In FIGS. 20A and 20B , a structure in which light emitted from the light-emitting element 3005 is emitted to the lower side (the substrate 3001 side) will be described.

As shown in FIGS. 20A and 20B , the light-emitting device 3000 has a double-sealing structure in which the light-emitting element 3005 is surrounded by a first sealing region 3007 and a second sealing region 3009 . By adopting the double-sealing structure, impurities (eg, water, oxygen, etc.) intruding into the light-emitting element 3005 side from the outside can be appropriately suppressed. However, it is not always necessary to provide the first sealing area 3007 and the second sealing area 3009 . For example, only the first sealing region 3007 may be provided.

Note that in FIG. 20B , the first sealing region 3007 and the second sealing region 3009 are provided in contact with the substrate 3001 and the substrate 3003 . However, not limited to this structure, for example, one or both of the first sealing region 3007 and the second sealing region 3009 may be provided in contact with an insulating film or a conductive film provided over the substrate 3001 . Alternatively, one or both of the first sealing region 3007 and the second sealing region 3009 may be provided in contact with an insulating film or a conductive film provided under the substrate 3003 .

The substrate 3001 and the substrate 3003 may have the same structures as those of the substrate 200 and the substrate 220 described in the above-described embodiments, respectively. The light-emitting element 3005 may have the same structure as the light-emitting element described in the above embodiment.

As the first sealing region 3007, a material containing glass (eg, glass frit, glass ribbon, etc.) can be used. As the second sealing region 3009, a material containing resin can be used. By using a material containing glass for the first sealing region 3007, productivity and sealing properties can be improved. In addition, by using a resin-containing material for the second sealing region 3009, impact resistance and heat resistance can be improved. However, the materials used for the first sealing region 3007 and the second sealing region 3009 are not limited thereto, the first sealing region 3007 may be formed using a material containing resin, and the second sealing region 3009 may be formed using a material containing glass.

The glass frit may contain, for example, magnesium oxide, calcium oxide, strontium oxide, barium oxide, cesium oxide, sodium oxide, potassium oxide, boron oxide, vanadium oxide, zinc oxide, tellurium oxide, aluminum oxide, silicon dioxide, lead oxide, oxide Tin, phosphorus oxide, ruthenium oxide, rhodium oxide, iron oxide, copper oxide, manganese dioxide, molybdenum oxide, niobium oxide, titanium oxide, tungsten oxide, bismuth oxide, zirconium oxide, lithium oxide, antimony oxide, lead borate glass, phosphoric acid Tin glass, vanadate glass or borosilicate glass. In order to absorb infrared light, the glass frit preferably contains one or more transition metals.

As the above-mentioned glass frit, for example, a glass frit paste is applied on a substrate and heated or irradiated with a laser beam. The glass frit paste contains the above-mentioned glass frit and a resin (also referred to as a binder) diluted with an organic solvent. In addition, an absorber that absorbs light of the wavelength of the laser beam may be added to the glass frit. For example, as the laser, an Nd:YAG laser, a semiconductor laser, or the like is preferably used. The laser beam shape can be circular or quadrangular.

As the above-mentioned resin-containing material, for example, polyester, polyolefin, polyamide (eg, nylon or aramid), polyimide, polycarbonate or acrylic resin, polyurethane, and epoxy resin can be used. Alternatively, a material containing a resin having a siloxane bond such as silicone can be used.

Note that when a glass-containing material is used as one or both of the first sealing region 3007 and the second sealing region 3009 , the thermal expansion coefficient of the glass-containing material is preferably close to that of the substrate 3001 . By adopting the above-described structure, it is possible to suppress the generation of cracks in the glass-containing material or the substrate 3001 due to thermal stress.

For example, in the case where a material containing glass is used for the first sealing region 3007 and a material containing resin is used for the second sealing region 3009, the following excellent effects can be obtained.

The second sealing region 3009 is provided closer to the outer peripheral portion side of the light emitting device 3000 than the first sealing region 3007 . In the light-emitting device 3000, the closer to the outer peripheral portion, the greater the strain due to external force or the like. Therefore, the side of the outer peripheral portion of the light-emitting device 3000 where greater strain is generated, that is, the second sealing region 3009 is sealed with a material containing resin, and the material provided inside the second sealing region 3009 is sealed with a material containing glass. Since the first sealing region 3007 is sealed, the light-emitting device 3000 is not easily damaged even if strain due to external force or the like occurs.

In addition, as shown in FIG. 20B , the first region 3011 corresponds to the region surrounded by the substrate 3001 , the substrate 3003 , the first sealing region 3007 , and the second sealing region 3009 . The second region 3013 corresponds to the region surrounded by the substrate 3001 , the substrate 3003 , the light-emitting element 3005 , and the first sealing region 3007 .

The first region 3011 and the second region 3013 are preferably filled with an inert gas such as a rare gas or nitrogen gas, for example. Alternatively, the first region 3011 and the second region 3013 are preferably filled with resin such as acrylic resin or epoxy resin. Note that the first region 3011 and the second region 3013 are preferably in a reduced pressure state rather than an atmospheric pressure state.

FIG. 20C shows a modification of the structure shown in FIG. 20B . FIG. 20C is a cross-sectional view showing a modification of the light emitting device 3000 .

FIG. 20C shows a structure in which a portion of the substrate 3003 is provided with a concave portion, and the concave portion is provided with a desiccant 3018 . Other structures are the same as those shown in FIG. 20B .

As the desiccant 3018, a substance that adsorbs moisture or the like by chemical adsorption or a substance that adsorbs moisture or the like by physical adsorption can be used. Examples of substances that can be used as desiccant 3018 include oxides of alkali metals, oxides of alkaline earth metals (eg, calcium oxide and barium oxide), sulfates, metal halides, perchlorates, zeolites, or Silicone etc.

Next, a modified example of the light emitting device 3000 shown in FIG. 20B will be described with reference to FIGS. 21A to 21D . Note that FIGS. 21A to 21D are cross-sectional views illustrating modified examples of the light emitting device 3000 shown in FIG. 20B .

In the light-emitting device shown in FIGS. 21A to 21D , the second sealing region 3009 is not provided, but only the first sealing region 3007 is provided. Furthermore, in the light-emitting device shown in FIGS. 21A to 21D , a region 3014 is provided in place of the second region 3013 shown in FIG. 20B .

As the region 3014, for example, polyester, polyolefin, polyamide (eg, nylon, aramid), polyimide, polycarbonate or acrylic resin, polyurethane, epoxy resin can be used. Alternatively, a material containing a resin having a siloxane bond such as silicone can also be used.

When the above-described materials are used for the region 3014, a so-called solid-sealed light-emitting device can be realized.

In the light-emitting device shown in FIG. 21B , a substrate 3015 is provided on the side of the substrate 3001 of the light-emitting device shown in FIG. 21A .

As shown in FIG. 21B , the substrate 3015 has irregularities. By arranging the substrate 3015 having concavities and convexities on the light extraction side of the light emitting element 3005, the light extraction efficiency of the light from the light emitting element 3005 can be improved. In addition, a substrate having the function of a diffusion plate may be provided instead of the structure having concavities and convexities shown in FIG. 21B .

In the light-emitting device shown in FIG. 21A , light is extracted through the substrate 3001 side, and on the other hand, in the light-emitting device shown in FIG. 21C , light is extracted through the substrate 3003 side.

The light-emitting device shown in FIG. 21C includes a substrate 3015 on the substrate 3003 side. The other structures are the same as those of the light-emitting device shown in FIG. 21B .

In the light-emitting device shown in FIG. 21D , the substrate 3003 and the substrate 3015 of the light-emitting device shown in FIG. 21C are not provided, but the substrate 3016 is provided.

The substrate 3016 includes a first concavity and convexity on a side closer to the light emitting element 3005 and a second concavity and convexity on a side farther from the light emitting element 3005 . By adopting the structure shown in FIG. 21D , the light extraction efficiency of the light from the light emitting element 3005 can be further improved.

Therefore, by using the structure shown in this embodiment mode, it is possible to provide a light-emitting device in which deterioration of the light-emitting element due to impurities such as moisture and oxygen is suppressed. Alternatively, by using the configuration shown in this embodiment mode, a light-emitting device with high light extraction efficiency can be realized.

Note that the structure shown in this embodiment mode can be appropriately combined with any structure shown in other embodiments.

(Embodiment 7)

In the present embodiment, an example in which the light-emitting element according to one embodiment of the present invention is applied to various lighting devices and electronic equipment will be described with reference to FIGS. 22A to 22C and FIG. 23 .

By manufacturing the light-emitting element according to one embodiment of the present invention on a flexible substrate, an electronic device or a lighting device including a light-emitting region having a curved surface can be realized.

In addition, the light-emitting device to which the light-emitting element according to one embodiment of the present invention is applied can also be applied to the lighting of automobiles, for example, the lighting is provided in a dashboard, a windshield, a ceiling, or the like.

FIG. 22A is a perspective view showing one side of the multifunction terminal 3500 , and FIG. 22B is a perspective view showing the other side of the multifunction terminal 3500 . A display unit 3504 , a camera 3506 , an illumination 3508 , and the like are incorporated in the housing 3502 of the multifunction terminal 3500 . The light emitting device of one embodiment of the present invention can be used for illumination 3508.

The illumination 3508 including the light emitting device of one embodiment of the present invention is used as a surface light source. Therefore, unlike point light sources represented by LEDs, the illumination 3508 can provide light emission with low directivity. For example, in the case where the illumination 3508 and the camera 3506 are used in combination, the camera 3506 can be used to shoot while the illumination 3508 is turned on or blinked. Because the lighting 3508 has the function of a surface light source, it is possible to obtain photos as if they were taken under natural light.

Note that the multifunction terminal 3500 shown in FIGS. 22A and 22B can have various functions like the electronic equipment shown in FIGS. 14A to 14G .

The frame 3502 may include a speaker, a sensor (the sensor has the function of measuring the following factors: force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness , electric field, current, voltage, electricity, radiation, flow, humidity, inclination, vibration, smell or infrared), microphone, etc. When a detection device having a sensor for detecting inclination such as a gyro sensor or an acceleration sensor is installed inside the multi-function terminal 3500, the orientation of the multi-function terminal 3500 can be determined (whether the multi-function terminal is arranged in the horizontal direction or in the vertical direction) ) to automatically switch the screen display of the display unit 3504.

In addition, the display unit 3504 may be used as an image sensor. For example, personal identification can be performed by photographing a palm print, a fingerprint, or the like when the display portion 3504 is touched with a palm or a finger. In addition, by providing a backlight or a sensing light source that emits near-infrared light in the display unit 3504, it is also possible to photograph finger veins, palm veins, and the like. Note that the light-emitting device of one embodiment of the present invention can be applied to the display portion 3504 .

22C is a perspective view of the safety light 3600. The safety light 3600 includes an illumination 3608 on the outside of the housing 3602, and the housing 3602 incorporates a speaker 3610 and the like. The light-emitting element of one embodiment of the present invention can be used for illumination 3608 .

Safety light 3600 illuminates when lighting 3608 is grasped or held, for example. An electronic circuit capable of controlling the light-emitting manner of the safety light 3600 may be provided inside the casing 3602 . The electronic circuit may be, for example, a circuit capable of emitting light once or several times intermittently, or a circuit capable of adjusting the amount of light emitted by controlling the current value of the light emission. Also, a circuit that emits a loud alarm sound from the speaker 3610 at the same time as the illumination 3608 emits light may be incorporated.

The Security Light 3600 is capable of emitting light in all directions, so it can emit light or emit light and sound to intimidate criminals, etc. In addition, the security light 3600 may include a camera such as a digital still camera having an imaging function.

FIG. 23 shows an example in which a light-emitting element is used in an indoor lighting device 8501. Since the light-emitting element can have a large area, a large-area lighting device can also be formed. In addition, the lighting device 8502 in which the light-emitting region has a curved surface can be formed by using a casing having a curved surface. Since the light-emitting element shown in this embodiment is in the form of a thin film, the degree of freedom in the design of the housing is high. Therefore, it is possible to form a lighting device that can respond to various designs. In addition, a large-scale lighting device 8503 may be installed on the wall of the room. In addition, a touch sensor may be provided in the lighting devices 8501, 8502, and 8503, and the power may be turned on and off.

In addition, when the light-emitting element is used for the surface side of the table, the lighting device 8504 having the function of the table can be realized. When the light-emitting element is used for a part of other furniture, a lighting device having the function of furniture can be realized.

As described above, by applying the light-emitting device of one embodiment of the present invention, a lighting device and an electronic device can be obtained. Note that the light-emitting device is not limited to the lighting device and the electronic device shown in this embodiment mode, and the light-emitting device can be applied to electronic devices in various fields.

The structure shown in this embodiment mode can be appropriately combined with any structure shown in other embodiment modes.

[Example 1]

In this example, 3,5-bis[3-(9H-2-methylcarbazol-9-yl)phenyl]pyridine (abbreviation: Me- The synthetic method of 35DCzPPy) (structural formula (100)) and the physical properties of the compound.

<Synthesis example 1>

1.5 g (6.4 mmol) of 3,5-dibromopyridine, 4.3 g (14 mmol) of 3-(2-methyl-9H-carbazol-9-yl)phenylboronic acid, 0.39 g of tris(o-tolyl)phosphine (1.3 mmol), 3.5 g (26 mmol) of potassium carbonate, 60 mL of toluene, 12 mL of ethanol and 6.0 mL of water were placed in a 200 mL three-necked flask. The mixture was degassed by stirring under reduced pressure, replacing the air in the flask with nitrogen. To this mixture was added 58 mg (0.26 mmol) of palladium (II) acetate, and the resulting mixture was stirred at 80° C. for 44 hours under a nitrogen stream. After a predetermined time, extraction was performed with toluene, and purification was performed by silica gel column chromatography (developing solvent: toluene) to obtain a yellow powder. The yellow powder was recrystallized from ethyl acetate to obtain 2.0 g of a white powder of the object of interest in a yield of 54%. The following (A-1) shows a synthesis scheme.

[Chemical formula 6]

2.0 g of the obtained white powder was purified by sublimation by gradient sublimation. In the sublimation purification, heating was performed at 310° C. under the conditions of a pressure of 2.2 Pa and an argon flow rate of 10 ml/min. After purification by sublimation, 1.2 g of a white solid of the object was obtained at a recovery rate of 60%.

The obtained solid was subjected to nuclear magnetic resonance spectroscopy ( ¹ H NMR), and the results are shown below.

¹ H NMR (chloroform-d, 300MHz): δ=8.94 (d, J=2.0Hz, 2H), 8.14 (t, J=1.9Hz, 1H), 8.08-8.12 (m, 2H), 8.02 (d, J=7.8Hz, 2H), 7.83-7.86(m, 2H), 7.72-7.77(m, 4H), 7.60-7.67(m, 2H), 7.33-7.44(m, 4H), 7.27-7.31(m, 2H), 7.20-7.24(m, 2H), 7.10-7.14(m, 2H).

24A and 24B show the ¹ H NMR spectrum of the obtained solid. Note that FIG. 24B is a spectrum diagram showing an enlarged portion of the range of 7.0 ppm to 9.0 ppm in FIG. 24A . The measurement results showed that Me-35DCzPPy of the target was obtained.

<Characteristics of Me-35DCzPPy>

Next, liquid chromatography-mass spectrometry (LC-MS analysis) was performed on the Me-35DCzPPy obtained in this example.

In the LC-MS analysis, liquid chromatography (LC) separation was performed using ACQUITY UPLC (manufactured by Waters Corporation), and mass spectrometry (MS) analysis was performed using Xevo G2Tof MS (manufactured by Waters Corporation). ACQUITY UPLC BEH C8 (2.1 x 100 mm, 1.7 μm) was used as the column used in the LC separation at a column temperature of 40°C. As mobile phase A, acetonitrile was used, and as mobile phase B, 0.1% aqueous formic acid was used. Additionally, Me-35DCzPPy was dissolved in toluene at an arbitrary concentration, and the mixture was diluted with acetonitrile to prepare a sample. The injection volume was 5.0 μL.

In LC separations, gradient methods are used that change the composition of the mobile phase. The ratio of mobile phase A to mobile phase B was 65:35 from 0 minutes to 1 minute after the start of measurement, and then the composition was changed, and the ratio of mobile phase A to mobile phase B was 95:5 10 minutes after the start of measurement. Change the composition linearly.

In MS analysis, ionization is performed by electrospray ionization (abbreviation: ESI) method. At this time, the capillary voltage and the sample cone voltage were set to 3.0 kV and 30 V, respectively, and detection was performed in the positive mode. The components ionized under the above conditions are collided with argon gas in the collision chamber to dissociate into product ions. The energy (collision energy) at the time of collision with argon was 70 eV. The mass range at the time of measurement is m/z=100 to 1200. FIG. 25 shows the results of detection of dissociated product ions by time-of-flight (TOF) type MS.

The result of FIG. 25 shows that the daughter ion of Me-35DCzPPy was detected mainly in the vicinity of m/z=574, the vicinity of m/z=409, and the vicinity of m/z=180. The results shown in FIG. 25 show features derived from Me-35DCzPPy, and thus can be regarded as important data for the identification of Me-35DCzPPy contained in the mixture.

Note that the product ion in the vicinity of m/z=574 is presumed to be a radical cation in a state in which the methyl group represented by C42H28N3 ^·+ ( ^·+ represents a radical cation) is removed from Me-35DCzPPy. The product ion in the vicinity of m/z=409 is presumed to be a radical positive ion in a state in which 2-methylcarbazole represented by C30H21N2 ^·+ is desorbed from Me-35DCzPPy. The product ion in the vicinity of m/z=180 is presumed to be a radical positive ion in a state in which 2-methylcarbazole represented by C13H10N ^·+ is desorbed from Me-35DCzPPy. This indicates that Me-35DCzPPy has a 2-methylcarbazole skeleton. Note that it is possible that the above-mentioned ±1 values of m/z are detected as protonation or desorbers of product ions.

Next, FIG. 26 shows the absorption spectrum and the emission spectrum of Me-35DCzPPy in the toluene solution. Figure 27 shows the absorption and emission spectra of thin films of Me-35DCzPPy. A solid thin film is formed on a quartz substrate by a vacuum evaporation method. The absorption spectrum of the toluene solution was measured using an ultraviolet-visible spectrophotometer (manufactured by JASCO Corporation, model V550). The absorption spectrum of Me-35DCzPPy in toluene solution shown in FIG. 26 was obtained by subtracting the absorption spectrum of toluene measured only by putting toluene in a quartz dish from the absorption spectrum of Me-35DCzPPy in toluene solution . The absorption spectrum of the thin film was measured using a spectrophotometer (Spectrophotometer U4100 manufactured by Hitachi High-Technologies Corporation). The emission spectrum was measured using a fluorescence spectrophotometer (manufactured by Hamamatsu Photonics Co., Ltd., Japan, FS920).

As can be seen from FIG. 26 , Me-35DCzPPy in the toluene solution has absorption peaks around 323 nm and 338 nm, and has a peak emission wavelength at 373 nm (excitation wavelength: 333 nm). As shown in FIG. 27 , the thin film of Me-35DCzPPy had absorption peaks around 210 nm, 243 nm, 295 nm, 326 nm, and 338 nm, and emission peaks around 350 nm and 382 nm (excitation wavelength: 300 nm). Since the Me-35DCzPPy of one embodiment of the present invention described above emits light, it can also be used as a light-emitting material.

The phosphorescence spectrum of the Me-35DCzPPy film was measured, and its T1 energy level was calculated. In this measurement, a LabRAM HR-PL (manufactured by Horiba, Japan) of a PL microscope, a He-Cd laser (325 nm) as excitation light, and a CCD detector were used, and the measurement temperature was 10K. The first peak on the short wavelength side of this phosphorescence is 451 nm (2.75 eV). This indicates that Me-35DCzPPy has a high T1 energy level and is suitable as a host for a luminescent center species emitting blue phosphorescence.

[Example 2]

In this example, a production example of a light-emitting element each containing an organic compound according to an embodiment of the present invention and the characteristics of the light-emitting element will be described. FIG. 28 is a cross-sectional view showing the structure of each element manufactured in this embodiment. Table 2 and Table 3 show the details of the element structure. In addition, the structure and abbreviation of the compound used here are shown below. Note that for other organic compounds, reference may be made to Example 1 and Embodiment 1.

In this embodiment, the light-emitting element 1 to the light-emitting element 6 are manufactured. In the light-emitting element 1, only 35DCzPPy was used as the host material of the light-emitting layer and the electron transport layer. In each of Light Emitting Element 2 to Light Emitting Element 6, 35DCzPPy and Me-35DCzPPy were used as an evaporation source for the host material of the light emitting layer and the material of the electron transport layer. Table 2 and Table 3 show the mixing ratio of 35DCzPPy and Me-35DCzPPy in each element.

Table 4 shows the physical property values of 35DCzPPy and Me-35DCzPPy used as the host material and the material of the electron transport layer. The difference between the property values of 35DCzPPy and Me-35DCzPPy is only a small difference between the HOMO levels.

[Chemical formula 7]

[Table 2]

[table 3]

x Light-emitting element 1 0 Light-emitting element 2 0.025 Light-emitting element 3 0.05 Light-emitting element 4 0.1 Light-emitting element 5 0.25 Light-emitting element 6 1

[Table 4]

material name HOMO level (eV) LUMO level (eV) T1 energy level (eV) 35DCzPPy -5.90 -2.39 2.75 Me-35DCzPPy -5.84 -2.39 2.75

<Manufacture of light-emitting element>

"Manufacture of Light-emitting Element 1 to Light-emitting Element 6"

As the electrode 101, an ITSO film with a thickness of 70 nm was formed on a glass substrate. The electrode area of the electrode 101 was set to 4 mm ² (2 mm×2 mm).

Next, as the hole injection layer 111, on the electrode 101, 1,3,5-tris(dibenzothiophen-4-yl) was deposited by co-evaporation at a weight ratio of DBT3P-II:MoO3 ₌ 1:0.5 Benzene (abbreviation: DBT3P-II) and MoO ₃ with a thickness of 20 nm.

Next, as the hole transport layer 112, on the hole injection layer 111, 9-phenyl-9H-3-(9-phenyl-9H-carbazol-3-yl)carbazole (abbreviated as: PCCP) with a thickness of 20 nm.

Next, as the light-emitting layer 160( 1 ), on the hole transport layer 112 , PCCP: 35DCzPPy:Me-35DCzPPy:Ir(mpptz-diPrp) ₃ =1:0.3×(1-x):0.3×:0.06 The weight ratios of PCCP, 35DCzPPy, Me-35DCzPPy and tris{2-[5-(2-methylphenyl)-4-(2,6-diisopropylphenyl)-4H-1 were deposited by co-evaporation, 2,4-Triazol-3-yl-κN ² ]phenyl-κC}iridium(III) (abbreviation: Ir(mpptz-diPrp) ₃ ), with a thickness of 30 nm, and then, as the light-emitting layer 160(2), with 35DCzPPy, Me-35DCzPPy and Ir(mpptz-diPrp) ₃ were deposited by co-evaporation at a weight ratio of 35DCzPPy:Me-35DCzPPy:Ir(mpptz-diPrp) ₃ =1-x:x:0.06 to a thickness of 10 nm. Note that in each of the light-emitting layer 160(1) and the light-emitting layer 160(2), Ir(mpptz-diPrp) ₃ is a guest material that emits phosphorescence. Note that the x value depends on the light emitting element, and Table 3 shows the x value in each light emitting element.

Next, as the first electron transport layer 118(1), on the light-emitting layer 160(2), 35DCzPPy and Me-35DCzPPy were deposited by co-evaporation at a weight ratio of 35DCzPPy:Me-35DCzPPy=1-x:x, with a thickness of 35DCzPPy and Me-35DCzPPy. 10nm. Then, as the second electron transport layer 118(2), on the first electron transport layer 118(1), phenanthroline (abbreviation: BPhen) was deposited by evaporation to a thickness of 15 nm. Note that the x value depends on each light emitting element, and Table 3 shows the x value in each light emitting element.

Next, as the electron injection layer 119, on the second electron transport layer 118(2), lithium fluoride (LiF) was deposited by vapor deposition to a thickness of 1 nm.

Next, as the electrode 102, aluminum (Al) was deposited on the electron injection layer 119 to a thickness of 200 nm.

Next, the light-emitting elements 1 to 6 were sealed by fixing the glass substrate for sealing to the glass substrate on which the organic material was deposited using a sealant for an organic EL device in a glove box in a nitrogen-containing atmosphere. Specifically, a sealant was applied to the periphery of the organic material on the glass substrate on which the organic material was deposited, the substrate and the glass substrate used for sealing were adhered, and then ultraviolet rays with a wavelength of 365 nm were irradiated at 6 J/cm ² . light, and heat treatment at 80°C for 1 hour. Through the above steps, the light-emitting element 1 to the light-emitting element 6 were obtained.

<Characteristics of light-emitting element>

Next, the characteristics of the manufactured light-emitting elements 1 to 6 were measured. In the measurement of luminance and CIE chromaticity, a colorimeter (BM-5A manufactured by TOPCON TECHNOHOUSE) was used. In the measurement of the electroluminescence spectrum, a multi-channel spectrum analyzer (PMA-11 manufactured by Hamamatsu Photonics Co., Ltd., Japan) was used.

FIG. 29 shows the current efficiency-brightness characteristics of the light-emitting elements 1 to 6. FIG. FIG. 30 shows luminance-voltage characteristics. Figure 31 shows external quantum efficiency-brightness characteristics. The measurement of each light-emitting element was performed at room temperature (in an atmosphere maintained at 23°C).

Table 5 shows the element characteristics of light-emitting elements 1 to 6 in the vicinity of 1000 cd/m ² .

[table 5]

FIG. 32 shows electroluminescence spectra when a current was supplied to the light-emitting elements 1 to 6 at a current density of 2.5 mA/cm ² .

As shown in FIGS. 29 , 30 , 31 , 32 , and Table 3, the maximum value of the external quantum efficiency of each of the light-emitting elements 1 to 6 was 26% or more. Therefore, all of the light-emitting elements 1 to 6 have extremely high external quantum efficiencies. Among them, the external quantum efficiency of the light-emitting element 1 in which the content of Me-35DCzPPy is 0 is particularly high.

In Table 5, the driving voltage around 1000 cd/m ² of each of the light-emitting elements 1 to 6 is 4.6 V or less, which is a low value as a light-emitting element emitting blue phosphorescence, and the light-emitting elements 1 to 6 each have good power efficiency. There was no large difference in driving voltage based on the difference in the mixing ratio of 35DCzPPy and Me-35DCzPPy.

As shown in FIG. 32 , the electroluminescence spectra of the light-emitting elements 1 to 6 each have peaks around 474 nm and 501 nm, and the full width at half maximum is about 68 nm, so the light-emitting elements 1 to 6 emit light blue light. There was no great difference in the electroluminescence spectrum based on the difference in the mixing ratio of 35DCzPPy and Me-35DCzPPy.

<Reliability of Light Emitting Elements>

Next, the light-emitting elements 1 to 6 were subjected to a driving test at a constant current of 2.5 mA/cm ² . Fig. 33 shows the result. As shown in FIG. 33 , the deterioration curves of the light-emitting elements 1 to 4 were similar to each other, and the luminance half-lives of the light-emitting elements 1 to 4 were all about 500 hours, which means high reliability. On the other hand, the light-emitting element 6 has a shorter luminance half-life than the light-emitting element 5, and the ratio of Me-35DCzPPy to 35DCzPPy in the light-emitting element 6 is higher than that in the light-emitting element 5. The light-emitting elements 5 and 6 each have a luminance half-life shorter than that of the light-emitting elements 1 to 4 . That is, when the percentage of the content of Me-35DCzPPy relative to the content of 35DCzPPy in the light-emitting element was 10% or less, there was no great difference in reliability, but when the content of Me-35DCzPPy relative to the content of 35DCzPPy in the light-emitting element increased When the percentage is more than 10%, the reliability of the light-emitting element is negatively affected. This is probably because the influence of the above-mentioned migration reaction of hydrogen atoms affects the concentration when the percentage of the content of Me-35DCzPPy relative to the content of 35DCzPPy is greater than 10%.

This means that, in order to obtain a light-emitting element having high reliability, the content of the organic compound in which the hydrogen atom of the carbazole skeleton is substituted with an alkyl group is preferably less than 10% of the host material.

Symbol Description

50: adhesive layer, 51: adhesive layer, 52: adhesive layer, 100: EL layer, 101: electrode, 102: electrode, 106: light-emitting unit, 108: light-emitting unit, 110: light-emitting unit, 111: hole injection layer, 112: hole transport layer, 113: electron transport layer, 114: electron injection layer, 114-a: electron injection layer, 114-b: electron injection layer, 115: charge generation layer, 116: hole injection layer , 117: hole transport layer, 118: electron transport layer, 119: electron injection layer, 130: light-emitting layer, 131: host material, 131_1: organic compound, 131_2: organic compound, 132: guest material, 140: light-emitting layer, 141: Host material, 141_1: Organic compound, 141_2: Organic compound, 142: Guest material, 150: Light-emitting element, 160: Light-emitting layer, 170: Light-emitting layer, 200: Substrate, 201: Resin layer, 202: Resin layer, 220: Substrate, 252: Light-emitting element, 300: Display device, 311: Electrode, 311b: Electrode, 340: Liquid crystal element, 351: Substrate, 360: Light-emitting element, 360b: Light-emitting element, 360g: Light-emitting element, 360r: Light-emitting element, 360w: Light-emitting element, 361: Substrate, 362: Display portion, 364: Circuit portion, 365: Wiring, 366: Circuit portion, 367: Wiring, 372: FPC, 373: IC, 374: FPC, 375: IC, 400: Display device, 401: Transistor, 402: Transistor, 403: Transistor, 404: Light-emitting element, 405: Capacitor, 406: Connection, 410: Pixel, 411: Insulating layer, 412: Insulating layer, 413: Insulating layer, 414: insulating layer, 415: insulating layer, 416: spacer, 417: adhesive layer, 419: connecting layer, 421: electrode, 422: EL layer, 423: electrode, 424: optical adjustment layer, 425: coloring layer, 426: light shielding layer, 451: opening, 471: substrate, 472: substrate, 476: insulating layer, 478: insulating layer, 501: transistor, 503: transistor, 505: capacitor, 506: connection, 511: insulating layer, 512: insulating layer, 513: insulating layer, 514: insulating layer, 517: adhesive layer, 519: connecting layer, 529: liquid crystal element, 543: connecting body, 545T: coumarin, 562: electrode, 563 : Liquid crystal, 564a: Alignment film, 564b: Alignment film, 572: Substrate, 576: Insulating layer, 578: Insulating layer, 599: Polarizer, 600A: ALS model, 601: Source side driver circuit, 602: Pixel Section, 603: Gate side driver circuit, 604: Sealing substrate, 605: Sealant, 607: Space, 608: Wiring, 610: Element substrate, 611: Switching TFT, 613: Electrode, 61 4: insulator, 616: EL layer, 617: electrode, 618: light-emitting element, 623: n-channel TFT, 624: p-channel TFT, 700: display panel, 701: resin layer, 702: resin layer, 800: display panel, 900: electronic device, 901: housing, 901a: housing, 901b: housing, 902: display unit, 903: hinge unit, 910: electronic device, 911a: housing, 911b: housing, 912: Display, 913: Hinge, 914a: Operation button, 914b: Operation button, 915: Case, 920: Electronic device, 921a: Case, 921b: Case, 922: Display, 923: Hinge, 1001 : substrate, 1002: base insulating film, 1003: gate insulating film, 1006: gate electrode, 1007: gate electrode, 1008: gate electrode, 1020: interlayer insulating film, 1021: interlayer insulating film, 1022: electrode, 1024B: electrode, 1024G: electrode, 1024R: electrode, 1025B: lower electrode, 1025G: lower electrode, 1025R: lower electrode, 1026: partition wall, 1028: EL layer, 1029: electrode, 1031: sealing substrate, 1032: sealing agent, 1033: base material, 1034B: colored layer, 1034G: colored layer, 1034R: colored layer, 1036: cover layer, 1037: interlayer insulating film, 1040: pixel portion, 1041: driver circuit portion, 1042: peripheral portion, 3000: Light-emitting device, 3001: Substrate, 3003: Substrate, 3005: Light-emitting element, 3007: Sealed region, 3009: Sealed region, 3011: Region, 3013: Region, 3014: Region, 3015: Substrate, 3016: Backing Bottom, 3018: Desiccant, 3054: Display, 3500: Multifunction Terminal, 3502: Frame, 3504: Display, 3506: Camera, 3508: Lighting, 3600: Lamp, 3602: Frame, 3608: Lighting, 3610 : Speaker, 6000: Display module, 6001: Top cover, 6002: Bottom cover, 6005: FPC, 6006: Display panel, 6009: Frame, 6010: Printed circuit board, 6011: Battery, 6015: Light-emitting section, 6016: Light-receiving section , 6017a: Light guide, 6017b: Light guide, 6018: Light, 7121: Frame, 7122: Display, 7123: Keyboard, 7124: Pointing device, 7200: Head-mounted display, 7201: Mounting, 7202: Lens , 7203: Main body, 7204: Display, 7205: Cable, 7206: Battery, 7300: Camera, 7301: Housing, 7302: Display, 7303: Operation buttons, 7304: Shutter button, 7305: Connection, 7306: Lens , 7400: Viewfinder, 7401: Frame, 7402: Display, 7403: Button, 7500: Head-mounted display, 7501: Frame, 7502: Display, 7503: Operation button, 7504: Fixing strap, 7505: Lens, 7510: Head-mounted display, 7701: Housing, 7702: Housing, 7703: Display, 7704: Operation keys, 7705: Lens, 7706: Connection, 8501: Lighting, 8502: Lighting, 8503: Lighting, 8504: Lighting, 9000 : Housing, 9001: Display, 9003: Speaker, 9005: Operation key, 9006: Connection terminal, 9007: Sensor, 9008: Microphone, 9050: Operation button, 9051: Information, 9052: Information, 9053: Information, 9054: information, 9055: hinge part, 9100: portable information terminal, 9101: portable information terminal, 9102: portable information terminal, 9200: portable information terminal, 9201: portable information terminal, 9300: television set, 9301: stand, 9311: remote control operation Machine, 9500: Display Unit, 9501: Display Panel, 9502: Display Area, 9503: Area, 9511: Shaft Section, 9512: Bearing Section, 9700: Automobile, 9701: Body, 9702: Wheel, 9703: Dashboard, 9704 : Lamp, 9710: Display, 9711: Display, 9712: Display, 9713: Display, 9714: Display, 9715: Display, 9721: Display, 9722: Display, 9723: Display.

This application is based on Japanese Patent Application No. 2016-253548 filed in the Japan Patent Office on December 27, 2016, the entire contents of which are hereby incorporated by reference.

Claims (8)

1. A light-emitting element, comprising: The EL layer between a pair of electrodes, Wherein, the EL layer includes a light-emitting layer, The light-emitting layer contains a first organic compound and a hydrocarbon-based substituent, the first organic compound contains a substituted or unsubstituted carbazole skeleton, The hydrocarbyl substituent has a structure in which at least one hydrogen atom of the first organic compound is substituted with a hydrocarbyl group having 1 to 6 carbon atoms, In addition, the weight ratio of the hydrocarbyl substituent to the first organic compound is greater than 0 and 0.025 or less. 2. The light-emitting element according to claim 1, wherein the hydrocarbon group substituent includes at least the hydrocarbon group having 1 to 6 carbon atoms at the 2-position of the carbazole skeleton. 3. The light-emitting element according to claim 1, wherein the hydrocarbon group having 1 to 6 carbon atoms is a methyl group. 4. A light-emitting element, comprising: The EL layer between a pair of electrodes, in: the EL layer includes a light-emitting layer, The light-emitting layer contains a first organic compound and a hydrocarbon-based substituent, The first organic compound is represented by the following general formula (G1),

A represents a substituted or unsubstituted nitrogen-containing heteroaromatic ring having 1 to 25 carbon atoms, Ar represents an arylene group having 6 to 13 carbon atoms, n represents 0 or 1, R ¹ to R ⁸ each independently represent hydrogen, a hydrocarbon group having 1 to 6 carbon atoms, a cyclic hydrocarbon group having 3 to 6 carbon atoms, and a substituted or unsubstituted aromatic hydrocarbon group having 6 to 25 carbon atoms. either, The hydrocarbyl substituent has a structure in which at least one hydrogen atom of the first organic compound is substituted with a hydrocarbyl group having 1 to 6 carbon atoms, and The weight ratio of the hydrocarbyl substituent to the first organic compound is greater than 0 and 0.025 or less. 5. A light-emitting element, comprising: The EL layer between a pair of electrodes, in: the EL layer includes a light-emitting layer, The light-emitting layer contains a first organic compound and a hydrocarbon-based substituent, The first organic compound is represented by the following general formula (G2),

A represents a substituted or unsubstituted nitrogen-containing six-membered heteroaromatic ring, Ar represents an arylene group having 6 to 13 carbon atoms, n represents 0 or 1, The hydrocarbyl substituent has a structure in which at least one hydrogen atom of the first organic compound is substituted with a hydrocarbyl group having 1 to 6 carbon atoms, and The weight ratio of the hydrocarbyl substituent to the first organic compound is greater than 0 and 0.1 or less. 6. The light-emitting element according to claim 5, The weight ratio of the hydrocarbyl substituent relative to the first organic compound is greater than 0 and less than 0.05. 7. The light-emitting element according to any one of claims 1, 4 and 5, wherein the light-emitting layer further comprises a guest material, And the guest material converts triplet excitation energy into luminescence. 8. The light-emitting element according to claim 7, The guest material exhibits a luminescence peak at 450 nm or more and 530 nm or less.

Images